Merge branch 'js/fix-merge-arg-quoting-in-rebase-p' into next

"git rebase -p" mangled log messages of a merge commit, which is
now fixed.

* js/fix-merge-arg-quoting-in-rebase-p:
rebase -p: fix incorrect commit message when calling `git merge`.

diff --cc git-rebase--interactive.sh
Simple merge