Add links to MP and resolve minor fixes

appengine/swarming/handlers_endpoints_test.py

Index: appengine/swarming/handlers_endpoints_test.py
diff --git a/appengine/swarming/handlers_endpoints_test.py b/appengine/swarming/handlers_endpoints_test.py
index dacf26d1080dfef5ab51989e506f399d2035ffa1..c25f49b973987e2dc6de875a300de1f0b910a22d 100755
--- a/appengine/swarming/handlers_endpoints_test.py
+++ b/appengine/swarming/handlers_endpoints_test.py
@@ -70,6 +70,9 @@ class ServerApiTest(BaseTest):
     """Asserts that server_details returns the correct version."""
     response = self.call_api('details')
     self.assertEqual({
+      'machine_provider_prefix': '',
+      'milo_prefix': '',
+      'sk_revision_prefix': '',
       'server_version': utils.get_app_version(),
       'bot_version': bot_code.get_bot_version('https://testbed.example.com'),
       }, response.json)