Escape string in regex pattern in timestamp test

Under PhantomJS 2.x, the output of `Date.toLocaleTimeString()` includes
'GMT+01:00', where the '+' needs to be escaped.

h/static/scripts/directive/test/timestamp-test.js

 'use strict';
 
 var angular = require('angular');
+var escapeStringRegexp = require('escape-string-regexp');
 
 var util = require('./util');
 
@@ -83,7 +84,7 @@ describe('timestamp', function () {
       // The exact format of the result will depend on the current locale,
       // but check that at least the current year and time are present
       assert.match(element.ctrl.absoluteTimestamp, new RegExp('.*2016.*' +
-        expectedDate.toLocaleTimeString()));
+        escapeStringRegexp(expectedDate.toLocaleTimeString())));
     });
   });
 });

package.json

@@ -37,6 +37,7 @@
     "dom-seek": "^1.0.1",
     "end-of-stream": "^1.1.0",
     "escape-html": "^1.0.3",
+    "escape-string-regexp": "^1.0.5",
     "exorcist": "^0.4.0",
     "extend": "^2.0.0",
     "gulp": "^3.9.1",