ssh not found by git because PATH has been unexpectedly changed

Started on 27-Aug-2014 16:48:45
Polling SCM changes on XXX
Using strategy: Default
[poll] Last Built Revision: Revision a9212bd3ddab1e9f9303be8d7db06cf8b4087b8b (origin/master)
 > git ls-remote -h git@XXX:XXX/XXX.git master # timeout=10
FATAL: hudson.plugins.git.GitException: Command "git ls-remote -h git@XXX:XXX/XXX.git master" returned status code 128:
stdout: 
stderr: error: cannot run ssh: No such file or directory
fatal: unable to fork

hudson.util.IOException2: hudson.plugins.git.GitException: Command "git ls-remote -h git@XXX:XXX/XXX.git master" returned status code 128:
stdout: 
stderr: error: cannot run ssh: No such file or directory
fatal: unable to fork

	at hudson.plugins.git.GitSCM.compareRemoteRevisionWith(GitSCM.java:462)
	at hudson.scm.SCM._compareRemoteRevisionWith(SCM.java:357)
	at hudson.scm.SCM.poll(SCM.java:374)
	at org.jenkinsci.plugins.multiplescms.MultiSCM.compareRemoteRevisionWith(MultiSCM.java:92)
	at hudson.scm.SCM._compareRemoteRevisionWith(SCM.java:357)
	at hudson.scm.SCM.poll(SCM.java:374)
	at hudson.model.AbstractProject.pollWithWorkspace(AbstractProject.java:1449)
	at hudson.model.AbstractProject._poll(AbstractProject.java:1420)
	at hudson.model.AbstractProject.poll(AbstractProject.java:1331)
	at com.cloudbees.jenkins.GitHubPushTrigger$1.runPolling(GitHubPushTrigger.java:73)
	at com.cloudbees.jenkins.GitHubPushTrigger$1.run(GitHubPushTrigger.java:98)
	at hudson.util.SequentialExecutionQueue$QueueEntry.run(SequentialExecutionQueue.java:118)
	at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
	at java.util.concurrent.FutureTask.run(FutureTask.java:166)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:724)
Caused by: hudson.plugins.git.GitException: Command "git ls-remote -h git@XXX:XXX/XXX.git master" returned status code 128:
stdout: 
stderr: error: cannot run ssh: No such file or directory
fatal: unable to fork

	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandIn(CliGitAPIImpl.java:1407)
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandWithCredentials(CliGitAPIImpl.java:1195)
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandWithCredentials(CliGitAPIImpl.java:1119)
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandWithCredentials(CliGitAPIImpl.java:1110)
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.getHeadRev(CliGitAPIImpl.java:2004)
	at hudson.plugins.git.GitSCM.compareRemoteRevisionWithImpl(GitSCM.java:495)
	at hudson.plugins.git.GitSCM.compareRemoteRevisionWith(GitSCM.java:460)
	... 18 more
Done. Took 20 ms
No changes