Merge branch 'git-p4' of git://repo.or.cz/git/git-p4

* 'git-p4' of git://repo.or.cz/git/git-p4:
  git-p4: Support usage of perforce client spec
  git-p4: git-p4 submit cleanups.
  git-p4: Removed git-p4 submit --direct.
  git-p4: Clean up git-p4 submit's log message handling.
  git-p4: Remove --log-substitutions feature.
  git-p4: support exclude paths