Increase wait timeout in test main.myisam-metadata, in an attempt to get rid...

Increase wait timeout in test main.myisam-metadata, in an attempt to get rid of Buildbot random failures.

mysql-test/t/myisam-metadata.test

@@ -35,7 +35,7 @@ send
   ALTER TABLE t1 ENABLE KEYS;
 
 --connection default
---let $wait_timeout=60
+--let $wait_timeout=600
 --let $show_statement= SHOW PROCESSLIST
 --let $field= State
 --let $condition= = 'Repair by sorting'