Bug 1186233 - Set test_packages_url correctly when running wpt from mozharness but outside of buildbot. r=jgraham

--HG--
extra : commitid : 81RUFAAXTwX

testing/mozharness/scripts/web_platform_tests.py

@@ -57,6 +57,7 @@ class WebPlatformTest(TestingMixin, MercurialScript, BlobUploadMixin):
         c = self.config
         self.installer_url = c.get('installer_url')
         self.test_url = c.get('test_url')
+        self.test_packages_url = c.get('test_packages_url')
         self.installer_path = c.get('installer_path')
         self.binary_path = c.get('binary_path')
         self.abs_app_dir = None