Fix spelling error

mysql-test/t/rpl_slave_status.test

@@ -9,7 +9,7 @@ start slave;
 connection master;
 --disable_warnings
 drop table if exists t1;
---enable_warning
+--enable_warnings
 create table t1 (n int);
 insert into t1 values (1);
 save_master_pos;

mysql-test/t/system_mysql_db_fix.test

@@ -27,7 +27,7 @@ CREATE TABLE db (
   KEY User (User)
 )
 type=ISAM;
---enable-warnings
+--enable_warnings
 
 INSERT INTO db VALUES ('%','test',   '','Y','Y','Y','Y','Y','Y');
 INSERT INTO db VALUES ('%','test\_%','','Y','Y','Y','Y','Y','Y');
@@ -45,7 +45,7 @@ CREATE TABLE host (
   PRIMARY KEY Host (Host,Db)
 )
 type=ISAM;
---enable-warnings
+--enable_warnings
 
 --disable_warnings
 CREATE TABLE user (
@@ -64,7 +64,7 @@ CREATE TABLE user (
   PRIMARY KEY Host (Host,User)
 )
 type=ISAM;
---enable-warnings
+--enable_warnings
 
 INSERT INTO user VALUES ('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y');
 INSERT INTO user VALUES ('localhost','',    '','N','N','N','N','N','N','N','N','N');