Merge branch 'sc/sequencer-gpg-octopus'

"git rebase --rebase-merges" did not correctly pass --gpg-sign
command line option to underlying "git merge" when replaying a merge
using non-default merge strategy or when replaying an octopus merge
(because replaying a two-head merge with the default strategy was
done in a separate codepath, the problem did not trigger for most
users), which has been corrected.

* sc/sequencer-gpg-octopus:
  t3435: add tests for rebase -r GPG signing
  sequencer: pass explicit --no-gpg-sign to merge
  sequencer: fix gpg option passed to merge subcommand

diff --cc sequencer.c
Simple merge