Merge branch 'pw/sequence-rerere-autoupdate' into next

Commands like "git rebase" accepted the --rerere-autoupdate option
from the command line, but did not always use it.  This has been
fixed.

* pw/sequence-rerere-autoupdate:
cherry-pick/revert: reject --rerere-autoupdate when continuing
cherry-pick/revert: remember --rerere-autoupdate
t3504: use test_commit
rebase -i: honor --rerere-autoupdate
rebase: honor --rerere-autoupdate
am: remember --rerere-autoupdate setting

diff --cc builtin/am.c
Simple merge

diff --cc sequencer.c
Simple merge