protobuf: skip show of zero-size repeated fields

Print "<empty>" message for such filed instead.

#2425
Signed-off-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Stanislav Kinsbursky <skinsbursky@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

protobuf.c

@@ -405,6 +405,11 @@ static void pb_show_repeated(pb_pr_ctl_t *ctl, int nr_fields, pb_pr_show_t show,
 	unsigned long counter;
 	int done;
 
+	if (nr_fields == 0) {
+		pr_msg("<empty>");
+		return;
+	}
+
 	field->count = nr_fields;
 	done = show(field);
 	if (done)