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

Update the use of API for consistency between two calls to
require_clean_work_tree() from the sequencer code.

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

wt-status.c

@@ -2655,8 +2655,12 @@ int require_clean_work_tree(struct repository *r,
 	}
 
 	if (err) {
-		if (hint)
+		if (hint) {
+			if (!*hint)
+				BUG("empty hint passed to require_clean_work_tree();"
+				    " use NULL instead");
 			error("%s", hint);
+		}
 		if (!gently)
 			exit(128);
 	}