Fixed MDEV-366: Assertion `share->reopen == 1' failed in maria_extra on DROP...

Fixed MDEV-366: Assertion `share->reopen == 1' failed in maria_extra on DROP TABLE which is locked twice

mysql-test/suite/maria/lock.result:
  Added test case
mysql-test/suite/maria/lock.test:
  Added test case
sql/sql_table.cc:
  One can't call HA_EXTRA_FORCE_REOPEN on something that may be opened twice.
  It's safe to remove the call in this case as we will call HA_EXTRA_PREPARE_FOR_DROP for the table anyway.
  (One nice side effect is that drop is a bit faster as we are not flushing the cache to disk before the drop anymore)

mysql-test/suite/maria/lock.result

@@ -27,3 +27,6 @@ i
 drop table t2;
 unlock tables;
 drop table t1;
+CREATE TABLE t1 (i INT) ENGINE=Aria;
+LOCK TABLES t1 WRITE, t1 AS t1a WRITE;
+DROP TABLE t1;

mysql-test/suite/maria/lock.test

@@ -42,3 +42,11 @@ select * from t1;
 drop table t2;
 unlock tables;
 drop table t1;
+
+#
+# MDEV-366: lock table twice with LOCK TABLES and then drop it
+#
+
+CREATE TABLE t1 (i INT) ENGINE=Aria;
+LOCK TABLES t1 WRITE, t1 AS t1a WRITE;
+DROP TABLE t1;

sql/sql_table.cc

@@ -2187,7 +2187,7 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
 
       if (thd->locked_tables_mode)
       {
-        if (wait_while_table_is_used(thd, table->table, HA_EXTRA_FORCE_REOPEN))
+        if (wait_while_table_is_used(thd, table->table, HA_EXTRA_NOT_USED))
         {
           error= -1;
           goto err;