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: I0c903ca9d566c89e4e0d6bd129dc1f7bc3e95db9

tripleo_common/exception.py

@@ -48,7 +48,7 @@ class TripleoCommonException(Exception):
             # kwargs doesn't match a variable in the message
             # log the issue and the kwargs
             LOG.exception(_LE('Exception in string format operation'))
-            for name, value in six.iteritems(kwargs):
+            for name, value in kwargs.items():
                 LOG.error(_LE("%(name)s: %(value)s"),
                           {'name': name, 'value': value})  # noqa
 

tripleo_common/image/base.py

@@ -12,9 +12,6 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-
-import six
-
 import json
 import os
 import yaml
@@ -74,7 +71,7 @@ class BaseImageManager(object):
                                                       attr)
 
                     # If a new key is introduced, add it.
-                    for key, value in six.iteritems(item):
+                    for key, value in item.items():
                         if key not in existing_image:
                             existing_image[key] = item[key]
 

undercloud_heat_plugins/immutable_resources.py

@@ -13,7 +13,6 @@
 
 import copy
 
-import six
 
 from heat.engine.resources.openstack.neutron import net
 from heat.engine.resources.openstack.neutron import port
@@ -32,7 +31,7 @@ class ImmutableNet(net.Net):
 
     properties_schema = {
         k: _copy_schema_immutable(v)
-        for k, v in six.iteritems(net.Net.properties_schema)
+        for k, v in net.Net.properties_schema.items()
     }
 
 
@@ -41,7 +40,7 @@ class ImmutablePort(port.Port):
 
     properties_schema = {
         k: _copy_schema_immutable(v)
-        for k, v in six.iteritems(port.Port.properties_schema)
+        for k, v in port.Port.properties_schema.items()
     }
 
 
@@ -50,7 +49,7 @@ class ImmutableSubnet(subnet.Subnet):
 
     properties_schema = {
         k: _copy_schema_immutable(v)
-        for k, v in six.iteritems(subnet.Subnet.properties_schema)
+        for k, v in subnet.Subnet.properties_schema.items()
     }