Removed reference to unexisting class Varien_Image_Adapter_ImagemagicExternal (#3242)

Author: fballiano

lib/Varien/Image/Adapter.php

@@ -18,7 +18,6 @@ class Varien_Image_Adapter
     public const ADAPTER_GD    = 'GD';
     public const ADAPTER_GD2   = 'GD2';
     public const ADAPTER_IM    = 'IMAGEMAGIC';
-    public const ADAPTER_IME   = 'IMAGEMAGIC_EXTERNAL';
 
     public static function factory($adapter)
     {
@@ -35,10 +34,6 @@ public static function factory($adapter)
                 return new Varien_Image_Adapter_Imagemagic();
                 break;
 
-            case self::ADAPTER_IME:
-                return new Varien_Image_Adapter_ImagemagicExternal();
-                break;
-
             default:
                 throw new Exception('Invalid adapter selected.');
                 break;