Merge branch 'pw/use-in-process-checkout-in-rebase'
Use an internal call to reset_head() helper function instead of
spawning "git checkout" in "rebase", and update code paths that are
involved in the change.
* pw/use-in-process-checkout-in-rebase:
rebase -m: don't fork git checkout
rebase --apply: set ORIG_HEAD correctly
rebase --apply: fix reflog
reset_head(): take struct rebase_head_opts
rebase: cleanup reset_head() calls
create_autostash(): remove unneeded parameter
reset_head(): make default_reflog_action optional
reset_head(): factor out ref updates
reset_head(): remove action parameter
rebase --apply: don't run post-checkout hook if there is an error
rebase: do not remove untracked files on checkout
rebase: pass correct arguments to post-checkout hook
t5403: refactor rebase post-checkout hook tests
rebase: factor out checkout for up to date branch