Proposed solution to JENKINS-15331

Introduces new configuration parameters, typically set using -D options when starting the Jenkins service.
-Dhudson.Util.deletionRetries=3
  Sets the number of times Jenkins will try to delete a file before giving up.
  Defaults to 3 attempts.

-Dhudson.Util.deletionRetryWait=100
  Sets the time (in milliseconds) for which Jenkins will pause between delete attempts.
  Defaults to 100ms between each attempt.
  If set to a negative number, it will delay for an increasing amount between attempts.

-Dhudson.Util.performGCOnFailedDelete=false
  If set to true, this tells Jenkins to run the Garbage Collector as well as waiting (just in case the process holding a file open is an un-garbage-collected Java filehandle within Jenkins itself).
  It defaults to false.

(Note: This was reworked to patch the Jenkins master branch as of 15:30 GMT April 11 2014)