Merge branch 'ld/git-p4-branches-and-labels'

* ld/git-p4-branches-and-labels:
git-p4: label import fails with multiple labels at the same changelist
git-p4: add test for p4 labels
git-p4: importing labels should cope with missing owner
git-p4: cope with labels with empty descriptions
git-p4: handle p4 branches and labels containing shell chars

diff --cc contrib/fast-import/git-p4
Simple merge