check for old password when changing passwords

settings/ajax/changepassword.php

@@ -10,7 +10,7 @@ $username = isset($_POST["username"]) ? $_POST["username"] : OC_User::getUser();
 $password = $_POST["password"];
 
 // Check if we are a user
-if( !OC_User::isLoggedIn() || (!OC_Group::inGroup( OC_User::getUser(), 'admin' )&& $username!=OC_User::getUser())) {
+if( !OC_User::isLoggedIn() || (!OC_Group::inGroup( OC_User::getUser(), 'admin' ) && ($username!=OC_User::getUser() || !OC_User::checkPassword($username,$password)))) {
 	echo json_encode( array( "status" => "error", "data" => array( "message" => "Authentication error" )));
 	exit();
 }