updated PDO_SQLSRV connection to use driverOptions in prepare-function

it seems that the `PDO::prepare` `$driver_options` param was never used.
in order to use the `PDOStatement::rowCount` function, the connection to an sql-server has to be established with the following params:
```
$connectionParams = array(
	'host' => $cfgHostName,
	'port' => $cfgPort,
	'dbname' => $cfgDatabase,
	'user' => $cfgUser,
	'password' => $cfgPassword,
	'driver' => 'pdo_sqlsrv',
	'driverOptions' => array(
		PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL
	)
);
```
the `driverOptions`-array is essential.
see http://msdn.microsoft.com/en-us/library/ff628176.aspx and http://at2.php.net/manual/de/pdo.prepare.php

with the follwing commit, the driver options are used by the PDO_SQLSRV prepared statements.
maybe there's a better way to implement this. please share your opinion on this fix.