Merge branch 'stable-3.6'

* stable-3.6: (26 commits)
  JGit v3.5.3.201412180710-r
  JGit v3.4.2.201412180340-r
  ObjectChecker: Disallow names potentially mapping to ".git" on HFS+
  ObjectChecker: Disallow Windows shortname "GIT~1"
  ObjectChecker: Disallow ".git." and ".git<space>"
  Always ignore case when forbidding .git in ObjectChecker
  DirCache: Refuse to read files with invalid paths
  DirCache: Replace isValidPath with DirCacheCheckout.checkValidPath
  Replace "a." with "a-" in unit tests
  Support the new repository layout for submodules
  Allow explicit configuration of git directory in CloneCommand
  Allow explicit configuration of git directory in InitCommand
  Fix tests on windows by closing repos
  RepoCommand should close opened repos
  Fix LocalDiskRepositoryTestCase to create correct type of repos
  Prevent NPE if ref can't be resolved when executing ReflogCommand
  Fix DirCacheCheckout to set correct file length if core.autocrlf=true
  CheckoutCommand: Fix checking out ours/theirs when no base stage exists
  Make sure modifications to config-param trustFolderStat are detected
  Apache HttpClientConnection: replace calls to deprecated LocalFile()
  ...

Change-Id: Ife6f21d64a148dbb0d0d9055356b1568188806fe