Add return value for mocked urllib3 request()

Mocked request() was returning MagicMock object, which caused
test_do_get() to fail. This was caused by what seems to be
inconsistent behaviour of MagicMock object on different
platforms in Python 2.7 [1].

Ubuntu 18.04, Python 2.7.5, mock 3.0.5:
    MagicMock() >= 400  -> True

CentOS-7, Python 2.7.5, mock 3.0.5:
    MagicMock() >= 400  -> False

Story: 2001245
Task: 36038

[1] https://github.com/testing-cabal/mock/issues/196

Change-Id: I7d41ec9abd87b4c799f4c7797d76da5350ca90bd

config_tempest/services/base.py

@@ -59,8 +59,9 @@ class Service(object):
             r = http.request('GET', url, headers=self.headers)
         except Exception as e:
             LOG.error("Request on service '%s' with url '%s' failed",
-                      (self.s_type, url))
+                      self.s_type, url)
             raise e
+
         if r.status >= 400:
             raise ServiceError("Request on service '%s' with url '%s' failed"
                                " with code %d" % (self.s_type, url, r.status))

config_tempest/tests/services/test_base.py

@@ -14,7 +14,6 @@
 # under the License.
 
 import mock
-import unittest
 
 from config_tempest.services.base import Service
 from config_tempest.services.base import VersionedService
@@ -37,9 +36,14 @@ class TestService(BaseServiceTest):
                                           self.FAKE_HEADERS)
         return expected_resp.data
 
-    @unittest.skip('Failing due to Storyboard: 2001245')
-    @mock.patch('config_tempest.api_discovery.urllib3')
+    @mock.patch('config_tempest.services.base.urllib3')
     def test_do_get(self, mock_urllib3):
+        mock_http = mock.Mock()
+        mock_r = mock.Mock()
+        mock_r.status = 200
+        mock_http.request.return_value = mock_r
+        mock_urllib3.PoolManager.return_value = mock_http
+
         resp = self.Service.do_get(self.FAKE_URL)
         expected_resp = self._mocked_do_get(mock_urllib3)
         self.assertEqual(resp, expected_resp)