This is almost reverted cherry-pick, and the implementation is
almost identical. It orders the input to merge differently to get
the effect and produces a different commit message with the
default author, rather than the original author.
Change-Id: I39970091d9f7406ae7168b8efaab23a5e2c16bad
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>