fix syntax error in create database with read_only in comments

Summary:
With `[SUPER_]READ_ONLY` in the comment section of `create database` statement,
the create will fail with syntax error (because the comment starting with
!version is parsed). The patch fixes it by ignoring the read_only keyword.
Database shouldn't be created in read_only state.

In addition, `[SUPER_]READ_ONLY` without assignment in `alter database` is also
ignored.

Test Plan: Added regression test cases.

Reviewers: jkedgar

Reviewed By: jkedgar

Subscribers: dreif, webscalesql-eng

Differential Revision: https://reviews.facebook.net/D58353

Author: tianx

mysql-test/r/db_read_only.result

@@ -791,6 +791,24 @@ show create database test_db_opt;
 Database	Create Database
 test_db_opt	CREATE DATABASE `test_db_opt` /*!40100 DEFAULT CHARACTER SET latin1 READ_ONLY */
 drop database test_db_opt;
+create database test_db_opt /*!40100 DEFAULT CHARACTER SET latin1 READ_ONLY*/;
+show create database test_db_opt;
+Database	Create Database
+test_db_opt	CREATE DATABASE `test_db_opt` /*!40100 DEFAULT CHARACTER SET latin1 */
+alter database test_db_opt read_only;
+show create database test_db_opt;
+Database	Create Database
+test_db_opt	CREATE DATABASE `test_db_opt` /*!40100 DEFAULT CHARACTER SET latin1 */
+drop database test_db_opt;
+create database test_db_opt /*!40100 DEFAULT CHARACTER SET latin1 SUPER_READ_ONLY*/;
+show create database test_db_opt;
+Database	Create Database
+test_db_opt	CREATE DATABASE `test_db_opt` /*!40100 DEFAULT CHARACTER SET latin1 */
+alter database test_db_opt super_read_only;
+show create database test_db_opt;
+Database	Create Database
+test_db_opt	CREATE DATABASE `test_db_opt` /*!40100 DEFAULT CHARACTER SET latin1 */
+drop database test_db_opt;
 connection default;
 alter database test read_only = false;
 show create database test;

mysql-test/t/db_read_only.test

@@ -197,6 +197,22 @@ alter database test_db_opt default collate = default;
 show create database test_db_opt;
 drop database test_db_opt;
 
+#
+# [super_]read_only is ignored in create database comment
+# and is ignored in alter without assignment
+#
+create database test_db_opt /*!40100 DEFAULT CHARACTER SET latin1 READ_ONLY*/;
+show create database test_db_opt;
+alter database test_db_opt read_only;
+show create database test_db_opt;
+drop database test_db_opt;
+
+create database test_db_opt /*!40100 DEFAULT CHARACTER SET latin1 SUPER_READ_ONLY*/;
+show create database test_db_opt;
+alter database test_db_opt super_read_only;
+show create database test_db_opt;
+drop database test_db_opt;
+
 #
 # cleanup
 #

sql/sql_yacc.yy

@@ -6496,7 +6496,8 @@ default_collation:
         ;
 
 db_read_only:
-          read_only_opt equal boolean_val
+          read_only_opt { /* Ignored */ }
+        | read_only_opt equal boolean_val
           {
             /* read_only = false */
             Lex->create_info.db_read_only= enum_db_read_only::DB_READ_ONLY_NO;