Merge branch 'ss/commit-dry-run-resolve-merge-to-no-op'

"git commit --dry-run" reported "No, no, you cannot commit." in one
case where "git commit" would have allowed you to commit, and this
improves it a little bit ("git commit --dry-run --short" still does
not give you the correct answer, for example).  This is a stop-gap
measure in that "commit --short --dry-run" still gives an incorrect
result.

* ss/commit-dry-run-resolve-merge-to-no-op:
  wt-status.c: set commitable bit if there is a meaningful merge.

wt-status.c

@@ -950,6 +950,7 @@ static void show_merge_in_progress(struct wt_status *s,
 			status_printf_ln(s, color,
 				_("  (fix conflicts and run \"git commit\")"));
 	} else {
+		s-> commitable = 1;
 		status_printf_ln(s, color,
 			_("All conflicts fixed but you are still merging."));
 		if (s->hints)