Merge branch 'ls/filter-process-delayed'

The filter-process interface learned to allow a process with long
latency give a "delayed" response.

* ls/filter-process-delayed:
  convert: add "status=delayed" to filter process protocol
  convert: refactor capabilities negotiation
  convert: move multiple file filter error handling to separate function
  convert: put the flags field before the flag itself for consistent style
  t0021: write "OUT <size>" only on success
  t0021: make debug log file name configurable
  t0021: keep filter log files on comparison

unpack-trees.c

@@ -380,6 +380,7 @@ static int check_updates(struct unpack_trees_options *o)
 	if (should_update_submodules() && o->update && !o->dry_run)
 		reload_gitmodules_file(index, &state);
 
+	enable_delayed_checkout(&state);
 	for (i = 0; i < index->cache_nr; i++) {
 		struct cache_entry *ce = index->cache[i];
 
@@ -394,6 +395,7 @@ static int check_updates(struct unpack_trees_options *o)
 			}
 		}
 	}
+	errs |= finish_delayed_checkout(&state);
 	stop_progress(&progress);
 	if (o->update)
 		git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);