Replace six.iteritems() with .items()

1.As mentioned in [1], we should avoid using six.iteritems to achieve
iterators. We can use dict.items instead, as it will return iterators
in PY3 as well. And dict.items/keys will more readable.
2.In py2, the performance about list should be negligible, see the
link [2].
[1] https://wiki.openstack.org/wiki/Python3
[2] http://lists.openstack.org/pipermail/openstack-dev/2015-June/066391.html

Change-Id: If5ab2f298e887a90cd43530e3fccc0294412f5c9

openstack/object_store/v1/obj.py

@@ -12,7 +12,6 @@
 # under the License.
 
 import copy
-import six
 
 from openstack.object_store import object_store_service
 from openstack.object_store.v1 import _base
@@ -168,7 +167,7 @@ class Object(_base.BaseResource):
         # Filter out items with empty values so the create metadata behaviour
         # is the same as account and container
         filtered_metadata = \
-            {key: value for key, value in six.iteritems(metadata) if value}
+            {key: value for key, value in metadata.items() if value}
 
         # Get a copy of the original metadata so it doesn't get erased on POST
         # and update it with the new metadata values.

openstack/profile.py

@@ -53,7 +53,6 @@ The resulting preference print out would look something like::
 
 import copy
 import logging
-import six
 
 from openstack.bare_metal import bare_metal_service
 from openstack.block_store import block_store_service
@@ -166,7 +165,7 @@ class Profile(object):
     def get_services(self):
         """Get a list of all the known services."""
         services = []
-        for name, service in six.iteritems(self._services):
+        for name, service in self._services.items():
             services.append(service)
         return services
 

openstack/telemetry/v2/capability.py

@@ -10,7 +10,6 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import six
 
 from openstack import resource2 as resource
 from openstack.telemetry import telemetry_service
@@ -34,5 +33,5 @@ class Capability(resource.Resource):
         resp = session.get(cls.base_path, endpoint_filter=cls.service,
                            params=params)
         resp = resp.json()
-        for key, value in six.iteritems(resp['api']):
+        for key, value in resp['api'].items():
             yield cls.existing(id=key, enabled=value)