Check usernames in the database as case insensitive, they are still stored...

Check usernames in the database as case insensitive, they are still stored case sensitive. Bug fix for oc-422 and oc-1514

lib/user/database.php

@@ -121,7 +121,7 @@ class OC_User_Database extends OC_User_Backend {
 	 * returns the user id or false
 	 */
 	public function checkPassword( $uid, $password ){
-		$query = OC_DB::prepare( 'SELECT `uid`, `password` FROM `*PREFIX*users` WHERE `uid` = ?' );
+		$query = OC_DB::prepare( 'SELECT `uid`, `password` FROM `*PREFIX*users` WHERE LOWER(`uid`) = LOWER(?)' );
 		$result = $query->execute( array( $uid));
 
 		$row=$result->fetchRow();
@@ -170,7 +170,7 @@ class OC_User_Database extends OC_User_Backend {
 	 * @return boolean
 	 */
 	public function userExists($uid){
-		$query = OC_DB::prepare( 'SELECT * FROM `*PREFIX*users` WHERE `uid` = ?' );
+		$query = OC_DB::prepare( 'SELECT * FROM `*PREFIX*users` WHERE LOWER(`uid`) = LOWER(?)' );
 		$result = $query->execute( array( $uid ));
 		
 		return $result->numRows() > 0;