Merge branch 'js/rebase-i-commit-cleanup-fix'

When "git rebase -i" processes "fixup" insn, there is no reason to
clean up the commit log message, but we did the usual stripspace
processing.  This has been corrected.

* js/rebase-i-commit-cleanup-fix:
  rebase -i: do leave commit message intact in fixup! chains

diff --cc t/t3415-rebase-autosquash.sh
Simple merge