sequencer.c: remove a stray semicolon

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer.c

@@ -4647,7 +4647,7 @@ int complete_action(struct replay_opts *opts, unsigned flags,
 
 	if (checkout_onto(opts, onto_name, oid_to_hex(&oid), orig_head))
 		return -1;
-;
+
 	if (require_clean_work_tree("rebase", "", 1, 1))
 		return -1;