Merge branch 'master' of git://people.freedesktop.org/~hausmann/git-p4

* 'master' of git://people.freedesktop.org/~hausmann/git-p4:
  git-p4: Cleanup, used common function for listing imported p4 branches
  git-p4: Fix upstream branch detection for submit/rebase with multiple branches.
  git-p4: Cleanup, make listExistingP4Branches a global function for later use.
  git-p4: input to "p4 files" by stdin instead of arguments
  git-p4: use subprocess in p4CmdList