Update Variable.php - Exception message
Update Variable.php - Exception message

Added the the filename in exception

"variable @test is undefined in F:/FILE_PATH/file.less"
TomArrow/less.php,oyejorge/less.php,iisisrael/less.php,oyejorge/less.php,atdt/less.php,iisisrael/less.php,TomArrow/less.php,atdt/less.php,oyejorge/less.php,TomArrow/less.php,iisisrael/less.php,atdt/less.php