YARN-1972. Added a secure container-executor for Windows. Contributed by Remus Rusanu.
commit ba7f31c2ee8d23ecb183f88920ef06053c0b9769 is the corresponding trunk commit, this is a slightly different patch for branch-2.
(cherry picked from commit 3326fba382350db88ccaa67625f92fa1dc5fd3e3)

Conflicts:
	hadoop-yarn-project/CHANGES.txt