GUACAMOLE-128: Stop propagation of "cut" events from within clipboard service event target.

guacamole/src/main/webapp/app/clipboard/services/clipboardService.js

@@ -86,6 +86,7 @@ angular.module('clipboard').factory('clipboardService', ['$injector',
     };
 
     // Prevent events generated due to execCommand() from disturbing external things
+    clipboardContent.addEventListener('cut',   stopEventPropagation);
     clipboardContent.addEventListener('copy',  stopEventPropagation);
     clipboardContent.addEventListener('paste', stopEventPropagation);