Overwriting user_agent in storage/datastore connection tests.

This prevents unnecessary HTTP requests to determine if GCE
is the current environment.

Author: dhermes

gcloud/datastore/test_connection.py

@@ -36,7 +36,10 @@ def _make_query_pb(self, kind):
         return pb
 
     def _makeOne(self, *args, **kw):
-        return self._getTargetClass()(*args, **kw)
+        conn = self._getTargetClass()(*args, **kw)
+        # Set the user agent so the user_agent is not lazily loaded.
+        setattr(conn, 'user_agent', 'gcloud-python/test')
+        return conn
 
     def _verifyProtobufCall(self, called_with, URI, conn):
         self.assertEqual(called_with['uri'], URI)

gcloud/storage/test_connection.py

@@ -22,7 +22,10 @@ def _getTargetClass(self):
         return Connection
 
     def _makeOne(self, *args, **kw):
-        return self._getTargetClass()(*args, **kw)
+        conn = self._getTargetClass()(*args, **kw)
+        # Set the user agent so the user_agent is not lazily loaded.
+        setattr(conn, 'user_agent', 'gcloud-python/test')
+        return conn
 
     def test_ctor_defaults(self):
         PROJECT = 'project'