Correct CREATE TABLE IF NOT EXISTS syntax for MSSQL (#26)

Author: Mr-Kaos

lib/PicoDb/Driver/Mssql.php

@@ -135,7 +135,7 @@ public function getLastId()
      */
     public function getSchemaVersion()
     {
-        $this->pdo->exec("CREATE TABLE IF NOT EXISTS [".$this->schemaTable."] ([version] INT DEFAULT '0')");
+        $this->pdo->exec("IF (OBJECT_ID('".$this->schemaTable."')) IS NULL CREATE TABLE [".$this->schemaTable."] ([version] INT DEFAULT '0')");
 
         $rq = $this->pdo->prepare('SELECT [version] FROM ['.$this->schemaTable.']');
         $rq->execute();