Remove check_string its not being used anymore.

includes/checkstring.php

@@ -1,30 +0,0 @@
-<?php
-/*
-	FusionPBX
-	Version: MPL 1.1
-
-	The contents of this file are subject to the Mozilla Public License Version
-	1.1 (the "License"); you may not use this file except in compliance with
-	the License. You may obtain a copy of the License at
-	http://www.mozilla.org/MPL/
-
-	Software distributed under the License is distributed on an "AS IS" basis,
-	WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
-	for the specific language governing rights and limitations under the
-	License.
-
-	The Original Code is FusionPBX
-
-	The Initial Developer of the Original Code is
-	Mark J Crane <[email protected]>
-	Portions created by the Initial Developer are Copyright (C) 2008-2012
-	the Initial Developer. All Rights Reserved.
-
-	Contributor(s):
-	Mark J Crane <[email protected]>
-*/
-function check_string($str) {
-    $str = str_replace ("\'", "''", $str); //escape the single quote
-    return $str;
-}
-?>