[DOC] This makes mysql_refresh() as described in
http://dev.mysql.com/doc/refman/6.0/en/mysql-refresh.html
available as mysqli_Refresh() and mysqli->refresh()
MYSQLI_REFRESH_BACKUP_LOG is only available when linking libmysql 6.0
or mysqlnd
Bug #44352 mysqli_connect_error() false negative for host errors
From now on the mysqli object doesn't have that magic properties, like
error, which were readable but not visible through isset(), property_exists()
and var_dump(). All other ext/mysqli classes were fixed too.
Now it will be easier to debug mysqli based applications.
