Quality-gates plugin does not work with SonarQube 6.3.

Since SonarQube 6.3, api has been removed/changed.

https://docs.sonarqube.org/display/DEV/API+Changes

Error message in Jenkins build log:
quality.gates.jenkins.plugin.QGException: Expected status 200, got: 404. Response: {"errors":[\{"msg":"Unknown url : /api/events"}]}
at quality.gates.sonar.api.SonarHttpRequester.executeGetRequest(SonarHttpRequester.java:59)
at quality.gates.sonar.api.SonarHttpRequester.getAPIInfo(SonarHttpRequester.java:47)
at quality.gates.sonar.api.QualityGatesProvider.getRequesterResult(QualityGatesProvider.java:34)
at quality.gates.sonar.api.QualityGatesProvider.getAPIResultsForQualityGates(QualityGatesProvider.java:29)
at quality.gates.jenkins.plugin.BuildDecision.getStatus(BuildDecision.java:20)
at quality.gates.jenkins.plugin.QGPublisher.perform(QGPublisher.java:73)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:779)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:720)
at hudson.model.Build$BuildExecution.post2(Build.java:186)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:665)
at hudson.model.Run.execute(Run.java:1758)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:97)
at hudson.model.Executor.run(Executor.java:405)
Build step 'Quality Gates' marked build as failure
Finished: FAILURE