Doing a clean install of Jenkins fails, presumably because of the corrupted version of the workflow multibranch plugin (2.9.1).

Steps to reproduce:

• Install Jenkins (2.19.2) on Ubuntu 16.10 server from the official Jenkins debian repository
• Run the setup procedure and install the recommended plugins
• Restart Jenkins

Expected: for Jenkins to successfully start

Actual: Jenkins fails to start with the following exceptions:

```
WARNING: Failed to load org.jenkinsci.plugins.orgfolder.github.MainLogic
java.lang.NoClassDefFoundError: org/jenkinsci/plugins/workflow/multibranch/WorkflowMultiBranchProject
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
at java.lang.Class.privateGetPublicMethods(Class.java:2902)
at java.lang.Class.getMethods(Class.java:1615)
at hudson.ExtensionFinder$GuiceFinder$SezpozModule.resolve(ExtensionFinder.java:477)
at hudson.ExtensionFinder$GuiceFinder$SezpozModule.configure(ExtensionFinder.java:506)
at com.google.inject.AbstractModule.configure(AbstractModule.java:62)
at com.google.inject.spi.Elements$RecordingBinder.install(Elements.java:230)
at com.google.inject.spi.Elements.getElements(Elements.java:103)
at com.google.inject.internal.InjectorShell$Builder.build(InjectorShell.java:136)
at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:104)
at com.google.inject.Guice.createInjector(Guice.java:96)
at com.google.inject.Guice.createInjector(Guice.java:73)
at hudson.ExtensionFinder$GuiceFinder.<init>(ExtensionFinder.java:280)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at java.lang.Class.newInstance(Class.java:442)
at net.java.sezpoz.IndexItem.instance(IndexItem.java:181)
at hudson.ExtensionFinder$Sezpoz._find(ExtensionFinder.java:634)
at hudson.ExtensionFinder$Sezpoz.find(ExtensionFinder.java:609)
at hudson.ClassicPluginStrategy.findComponents(ClassicPluginStrategy.java:478)
at hudson.ExtensionList.load(ExtensionList.java:349)
at hudson.ExtensionList.ensureLoaded(ExtensionList.java:287)
at hudson.ExtensionList.getComponents(ExtensionList.java:167)
at jenkins.model.Jenkins$8.onInitMilestoneAttained(Jenkins.java:1069)
at jenkins.InitReactorRunner$1.onAttained(InitReactorRunner.java:82)
at org.jvnet.hudson.reactor.ReactorListener$Aggregator.onAttained(ReactorListener.java:104)
at org.jvnet.hudson.reactor.Reactor$1.run(Reactor.java:176)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: org.jenkinsci.plugins.workflow.multibranch.WorkflowMultiBranchProject
at jenkins.util.AntClassLoader.findClassInComponents(AntClassLoader.java:1373)
at jenkins.util.AntClassLoader.findClass(AntClassLoader.java:1326)
at jenkins.util.AntClassLoader.loadClass(AntClassLoader.java:1079)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 34 more
```

And then later down:

```
SEVERE: Failed to initialize Jenkins
hudson.util.HudsonFailedToLoad: org.jvnet.hudson.reactor.ReactorException: java.lang.Error: java.lang.reflect.InvocationTargetException
at hudson.WebAppMain$3.run(WebAppMain.java:248)
Caused by: org.jvnet.hudson.reactor.ReactorException: java.lang.Error: java.lang.reflect.InvocationTargetException
at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:269)
at jenkins.InitReactorRunner.run(InitReactorRunner.java:47)
at jenkins.model.Jenkins.executeReactor(Jenkins.java:1062)
at jenkins.model.Jenkins.<init>(Jenkins.java:905)
at hudson.model.Hudson.<init>(Hudson.java:85)
at hudson.model.Hudson.<init>(Hudson.java:81)
at hudson.WebAppMain$3.run(WebAppMain.java:231)
Caused by: java.lang.Error: java.lang.reflect.InvocationTargetException
at hudson.init.TaskMethodFinder.invoke(TaskMethodFinder.java:110)
at hudson.init.TaskMethodFinder$TaskImpl.run(TaskMethodFinder.java:175)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:282)
at jenkins.model.Jenkins$7.runTask(Jenkins.java:1038)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:210)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at hudson.init.TaskMethodFinder.invoke(TaskMethodFinder.java:104)
... 8 more
Caused by: java.lang.NullPointerException
at hudson.plugins.git.GitSCM.onLoaded(GitSCM.java:1719)
... 13 more
```

Workaround:

• stop jenkins (`/etc/init.d/jenkins stop`)
• go to `/var/lib/jenkins/plugins/` and remove the corrupt workflow multibranch plugin (`workflow-multibranch-plugin.jpi` and the `workflow-multibranch-pluging` folder)
• download the latest workflow multibranch plugin (2.9.2 - http://updates.jenkins-ci.org/download/plugins/workflow-multibranch/2.9.2/workflow-multibranch.hpi), put it into the plugins directory
• start jenkins (`/etc/init.d/jenkins start`)

I'm not sure, but the fact that the workflow multibranch plugin page still lists 2.9.1 as the "Latest Release", even though 2.9.2 is released and the change notes say that 2.9.1 is corrupted might be related: https://wiki.jenkins-ci.org/display/JENKINS/Pipeline+Multibranch+Plugin