[FIXED JENKINS-19515] Try to avoid truncation of fingerprint storage files.
1. Use AtomicFileWriter on the hypothesis that an exception during save() caused truncation.
2. Improve logging from the cleanup thread since that may be related to the root cause.
3. Regardless of the cause, recover more gracefully by deleting any truncated file rather than throwing the error up.
Merge REMERGE_HEAD into HEAD
Trying to diagnose an NPE associated with cloudbees-template.
In 1.516:
java.lang.NullPointerException
	at hudson.maven.ModuleName.equals(ModuleName.java:115)
	at hudson.maven.MavenModuleSet.reconfigure(MavenModuleSet.java:1108)
	at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.parsePoms(MavenModuleSetBuild.java:907)
	at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.doRun(MavenModuleSetBuild.java:631)
Run.getResult may be null, so check for that.
Observed in 1.509.2:
Parsing POMs
Failed to transfer Could not find artifact … in central (http://repo.maven.apache.org/maven2)
Archiving artifacts
ERROR: Processing failed due to a bug in the code. Please report this to jenkinsci-users@googlegroups.com
java.lang.NullPointerException
	at hudson.tasks.ArtifactArchiver.perform(ArtifactArchiver.java:138)
	at org.zeroturnaround.jenkins.LiveRebelDeployBuilder.getArtificatOrMetadata(LiveRebelDeployBuilder.java:194)
	at org.zeroturnaround.jenkins.LiveRebelDeployBuilder.uploadConfiguration(LiveRebelDeployBuilder.java:171)
	at org.zeroturnaround.jenkins.LiveRebelDeployBuilder.perform(LiveRebelDeployBuilder.java:108)
	at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19)
	at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:812)
	at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.build(MavenModuleSetBuild.java:828)
	at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.doRun(MavenModuleSetBuild.java:779)
	at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:594)
	at hudson.model.Run.execute(Run.java:1575)
	at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:485)
creating an RC branch