adding port parameter to the mysqli instantiation

mysqli passes the port in as a parameter versus mysql_connect()'s method of using the hostname http://localhost:8889. http://www.php.net/manual/en/mysqli.construct.php This change will allow you to specify a port in the config that gets used when setting up the connection. I found it useful when utilizing this with MAMP when the default port is 8889 for MySQL.

Related phabricator change to support ports: https://github.com/facebook/phabricator/pull/356