Merge branch 'ef/maint-rebase-error-message' into maint

When "git rebase" was given a bad commit to replay the history on,
its error message did not correctly give the command line argument
it had trouble parsing.

By Erik Faye-Lund
* ef/maint-rebase-error-message:
  rebase: report invalid commit correctly

diff --cc git-rebase.sh
Simple merge