Merge branch 'sh/p4-multi-depot'

"git p4" when interacting with multiple depots at the same time
used to incorrectly drop changes.

* sh/p4-multi-depot:
  git-p4: reduce number of server queries for fetches
  git-p4: support multiple depot paths in p4 submit
  git-p4: failing test case for skipping changes with multiple depots

diff --cc git-p4.py
Simple merge