Fix blocking MyISAM tables when IF NOT EXISTS is used

Summary:
The check to block creating MyISAM tables suffered
from an error with operator precedence, which prevented it
from blocking creation when the user specified IF NOT EXISTS.

Test Plan: Modified existing test to include case.

Reviewers: santoshb

Reviewed By: santoshb

mysql-test/r/create_myisam_table.result

@@ -8,6 +8,12 @@ create table myisam_table (a int) ENGINE=MYISAM;
 ERROR HY000: Non-temporary MyISAM tables cannot be created outside mysql schema.
 create table mysql.myisam_table (a int) ENGINE=MYISAM;
 create table innodb_table (a int) ENGINE=INNODB;
+create table if not exists mysql.myisam_table (a int) ENGINE=MYISAM;
+Warnings:
+Note	1050	Table 'myisam_table' already exists
+create table if not exists mysql.myisam_table2 (a int) ENGINE=MYISAM;
+create table if not exists myisam_table (a int) ENGINE=MYISAM;
+ERROR HY000: Non-temporary MyISAM tables cannot be created outside mysql schema.
 alter table innodb_table ENGINE=MYISAM;
 ERROR HY000: Non-temporary MyISAM tables cannot be created outside mysql schema.
 alter table mysql.mysql_table ENGINE=MYISAM;
@@ -19,3 +25,4 @@ alter table test.innodb_table ENGINE=MYISAM;
 ERROR HY000: Non-temporary MyISAM tables cannot be created outside mysql schema.
 drop table mysql_table;
 drop table myisam_table;
+drop table myisam_table2;

mysql-test/t/create_myisam_table.test

@@ -9,6 +9,12 @@ create table myisam_table (a int) ENGINE=MYISAM;
 create table mysql.myisam_table (a int) ENGINE=MYISAM;
 create table innodb_table (a int) ENGINE=INNODB;
 
+# Check behavior when called with IF NOT EXISTS
+create table if not exists mysql.myisam_table (a int) ENGINE=MYISAM;
+create table if not exists mysql.myisam_table2 (a int) ENGINE=MYISAM;
+-- error ER_BLOCK_MYISAM_TABLES
+create table if not exists myisam_table (a int) ENGINE=MYISAM;
+
 -- error ER_BLOCK_MYISAM_TABLES
 alter table innodb_table ENGINE=MYISAM;
 alter table mysql.mysql_table ENGINE=MYISAM;
@@ -21,3 +27,4 @@ use mysql;
 alter table test.innodb_table ENGINE=MYISAM;
 drop table mysql_table;
 drop table myisam_table;
+drop table myisam_table2;

sql/sql_parse.cc

@@ -8473,7 +8473,7 @@ bool block_myisam_tables(HA_CREATE_INFO *create_info,
       strcmp(table_list->db, "mtr") &&
       create_info->db_type &&
       create_info->db_type->db_type == DB_TYPE_MYISAM &&
-      !create_info->options & HA_LEX_CREATE_TMP_TABLE)
+      !(create_info->options & HA_LEX_CREATE_TMP_TABLE))
     return true;
   return false;
 }