Clean imports in code

In some part in the code we import objects. In the Openstack style guidelines
they recommend to import only modules. [1]: "Do not import objects, only modules".

[1] https://docs.openstack.org/hacking/0.10.3/

Change-Id: Id4b47eeae1d3e86a3cb259c32fcb376ffbd3f8c7

novaclient/base.py

@@ -28,7 +28,7 @@ import threading
 
 from oslo_utils import reflection
 from oslo_utils import strutils
-from requests import Response
+import requests
 import six
 
 from novaclient import exceptions
@@ -103,7 +103,7 @@ class RequestIdMixin(object):
             self._append_request_id(resp)
 
     def _append_request_id(self, resp):
-        if isinstance(resp, Response):
+        if isinstance(resp, requests.Response):
             # Extract 'x-openstack-request-id' from headers if
             # response is a Response object.
             request_id = (resp.headers.get('x-openstack-request-id') or

novaclient/tests/unit/test_base.py

@@ -11,7 +11,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from requests import Response
+import requests
 import six
 
 from novaclient import api_versions
@@ -23,13 +23,13 @@ from novaclient.v2 import flavors
 
 
 def create_response_obj_with_header():
-    resp = Response()
+    resp = requests.Response()
     resp.headers['x-openstack-request-id'] = fakes.FAKE_REQUEST_ID
     return resp
 
 
 def create_response_obj_with_compute_header():
-    resp = Response()
+    resp = requests.Response()
     resp.headers['x-compute-request-id'] = fakes.FAKE_REQUEST_ID
     return resp