code: function(imageIdentifier, callback) {
          var url = this.getImageUrl(imageIdentifier).setPath('/shorturls'),
              signed = this.getSignedResourceUrl('DELETE', url);
  
          request.del(signed, callback);
          return this;
      }
docs: Delete all ShortUrls for a given imageIdentifier
  
  @param {String}   imageIdentifier
  @param {Function} callback
  @return {ImboClient}