Merge branch 'ob/sequencer-empty-hint-fix'

The use of API for consistency between two calls to
require_clean_work_tree() from the sequencer code has been cleaned
up.

* ob/sequencer-empty-hint-fix:
  sequencer: rectify empty hint in call of require_clean_work_tree()

diff --cc sequencer.c
Simple merge

diff --cc wt-status.c
Simple merge