Fix for MDEV-15105 (memory loss with LOCK sequence)

MDEV 15105 "Bytes lost and Assertion `global_status_var.global_memory_used == 0' fails on shutdown after attempts
to LOCK/RENAME sequence"

mysql-test/suite/sql_sequence/rename.result

+CREATE SEQUENCE seq1;
+RENAME TABLE seq1 TO seq2, seq3 TO seq4;
+ERROR 42S02: Table 'test.seq3' doesn't exist
+LOCK TABLE seq1 READ;
+UNLOCK TABLES;
+drop table seq1;

mysql-test/suite/sql_sequence/rename.test

+CREATE SEQUENCE seq1;
+--error ER_NO_SUCH_TABLE
+RENAME TABLE seq1 TO seq2, seq3 TO seq4;
+LOCK TABLE seq1 READ;
+UNLOCK TABLES;
+drop table seq1;

sql/sql_sequence.cc

@@ -439,7 +439,7 @@ int SEQUENCE::read_initial_values(TABLE *table)
     DBUG_ASSERT(table->reginfo.lock_type == TL_READ);
     if (!(error= read_stored_values(table)))
       initialized= SEQ_READY_TO_USE;
-    mysql_unlock_tables(thd, lock, 0);
+    mysql_unlock_tables(thd, lock);
     if (mdl_lock_used)
       thd->mdl_context.release_lock(mdl_request.ticket);