builtin/send-pack: fix leaking list of push options

The list of push options is leaking. Plug the leak.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/send-pack.c

@@ -340,6 +340,7 @@ int cmd_send_pack(int argc,
 		/* stable plumbing output; do not modify or localize */
 		fprintf(stderr, "Everything up-to-date\n");
 
+	string_list_clear(&push_options, 0);
 	free_refs(remote_refs);
 	free_refs(local_refs);
 	refspec_clear(&rs);