fixed how the attributes are being pulled based on MySQL document:

* Relay_Log_Size should be max_relay_log_size in system variable: http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html#sysvar_max_relay_log_size
* Slave_open_temp_tables should be in global variables: http://dev.mysql.com/doc/refman/5.5/en/server-status-variables.html#statvar_Slave_open_temp_tables
* Slave_retried_transactions should be in global variables: http://dev.mysql.com/doc/refman/5.5/en/server-status-variables.html#statvar_Slave_retried_transactions