GUAC-791: Add missing private tags to inner variables/functions.

guacamole-common-js/src/main/webapp/modules/DataURIReader.js

@@ -43,6 +43,7 @@ Guacamole.DataURIReader = function(stream, mimetype) {
     /**
      * Current data URI.
      *
+     * @private
      * @type {String}
      */
     var uri = 'data:' + mimetype + ';base64,';