read-cache.c: don't guard calls to progress.c API

Don't guard the calls to the progress.c API with "if (progress)". The
API itself will check this. This doesn't change any behavior, but
makes this code consistent with the rest of the codebase.

See ae9af12287 (status: show progress bar if refreshing the index
takes too long, 2018-09-15) for the commit that added the pattern
we're changing here.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

read-cache.c

@@ -1584,8 +1584,7 @@ int refresh_index(struct index_state *istate, unsigned int flags,
 		t2_sum_scan += t2_did_scan;
 		if (new_entry == ce)
 			continue;
-		if (progress)
-			display_progress(progress, i);
+		display_progress(progress, i);
 		if (!new_entry) {
 			const char *fmt;
 
@@ -1620,10 +1619,8 @@ int refresh_index(struct index_state *istate, unsigned int flags,
 	trace2_data_intmax("index", NULL, "refresh/sum_lstat", t2_sum_lstat);
 	trace2_data_intmax("index", NULL, "refresh/sum_scan", t2_sum_scan);
 	trace2_region_leave("index", "refresh", NULL);
-	if (progress) {
-		display_progress(progress, istate->cache_nr);
-		stop_progress(&progress);
-	}
+	display_progress(progress, istate->cache_nr);
+	stop_progress(&progress);
 	trace_performance_leave("refresh index");
 	return has_errors;
 }