diff.c: use ALLOC_GROW()

Use ALLOC_GROW() instead of open-coding it in diffstat_add() and
diff_q().

Signed-off-by: Dmitry S. Dolzhenko <dmitrys.dolzhenko@yandex.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c

@@ -1361,11 +1361,7 @@ static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 {
 	struct diffstat_file *x;
 	x = xcalloc(sizeof (*x), 1);
-	if (diffstat->nr == diffstat->alloc) {
-		diffstat->alloc = alloc_nr(diffstat->alloc);
-		diffstat->files = xrealloc(diffstat->files,
-				diffstat->alloc * sizeof(x));
-	}
+	ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
 	diffstat->files[diffstat->nr++] = x;
 	if (name_b) {
 		x->from_name = xstrdup(name_a);
@@ -3965,11 +3961,7 @@ struct diff_queue_struct diff_queued_diff;
 
 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
 {
-	if (queue->alloc <= queue->nr) {
-		queue->alloc = alloc_nr(queue->alloc);
-		queue->queue = xrealloc(queue->queue,
-					sizeof(dp) * queue->alloc);
-	}
+	ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
 	queue->queue[queue->nr++] = dp;
 }