recovery: remove dead code, add a comment

src/box/lua/info.c

@@ -136,6 +136,12 @@ lbox_info_replication(struct lua_State *L)
 static int
 lbox_info_server(struct lua_State *L)
 {
+	/*
+	 * Self can be NULL during bootstrap: entire box.info
+	 * bundle becomes available soon after entering box.cfg{}
+	 * and replication bootstrap relies on this as it looks
+	 * at box.info.status.
+	 */
 	struct replica *self = replica_by_uuid(&INSTANCE_UUID);
 	lua_createtable(L, 0, 2);
 	lua_pushliteral(L, "id");

src/box/replication.cc

@@ -158,7 +158,6 @@ void
 replica_clear_id(struct replica *replica)
 {
 	assert(replica->id != REPLICA_ID_NIL && replica->id != instance_id);
-
 	/*
 	 * Don't remove replicas from vclock here.
 	 * The vclock_sum() must always grow, it is a core invariant of
@@ -168,8 +167,6 @@ replica_clear_id(struct replica *replica)
 	 * Some records may arrive later on due to asynchronous nature of
 	 * replication.
 	 */
-	if (instance_id == replica->id)
-		instance_id = REPLICA_ID_NIL;
 	replica->id = REPLICA_ID_NIL;
 	if (replica_is_orphan(replica)) {
 		replicaset_remove(&replicaset, replica);