Add the --unlink option to mirror

This deletes the local file before tearing down the mirror connection,
allowing us to avoid an ambiguous recovery situation.

src/client.c

@@ -476,7 +476,7 @@ int client_serve_request(struct client* client)
 	}
 	server_unlock_io( client->serve );
 
-	return failure;
+	return stop;
 }