Issue webcompat#986. Fix bug when removing uploaded image.

Author: Mike Taylor

webcompat/static/js/lib/bugform.js

@@ -278,7 +278,7 @@ function BugForm() {
     uploadWrapper.addClass('is-hidden');
     removeBanner.on('click', _.bind(function() {
       // clear out the input value, remove the preview and hide the banner
-      this.uploadField.val(this.uploadField.get().defaultValue);
+      this.uploadField.val(this.uploadField.get(0).defaultValue);
       label.css('background', 'none');
       removeBanner.addClass('is-hidden');
       uploadWrapper.removeClass('is-hidden');