#1406 silently skipped the call to moveDirectory in case newBuildDir.isDirectory(), rather than throwing an IOE as renameTo does.
Also deleting apparently useless call to forceMkdir.

[FIXED JENKINS-25788] RunMap.remove was always returning false, even when the Run was in fact removed.

Tested on a windows box to automaticaly install 1.4, 1.5, 1.6, 1.7 and 1.8 JDKs

[FIXED JENKINS-23797] Produce human readable output in DiskSpaceMonitorDescriptor.DiskSpace.toString()

This makes the overall appearance of the page match what you would actually see from the console.
(Using: java -jar jenkins-cli.jar -s <URL> help <COMMAND>)
For some commands, such as SupportCommand (in support-core), this is critical,
since the expectation is that longDescription is a multiline fixed-width block.

During master restart only attempt to reconnect the slave after the master has
finished restarting.

- There is still the issue with adding isConnecting() polluting the NodeProvisioner, but this is
  a simple, low risk but important change

Not fully solved, since the scannedDirs field can still grow to be large, but at least clearing files/dirsNotIncluded.
Also imposing a 5s timeout on the scan regardless of file count, and defining a user-customizable bound.

[JENKINS-25691] Might have prevented the need for: https://github.com/jenkinsci/maven-plugin/pull/33

ssh-slaves plugin can leverage this to try to obtain the state of the slave JVM via SSH.

Reference: ZD-23093

Reference: http://bugs.java.com/bugdatabase/view_bug.do?bug_id=8051847
Reference: ZD-23093

Reference: ZD-23093