Replace six.iteritems() with .items()

1.As mentioned in [1], we should avoid usingg
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: I71c13040318eca6e5ed993e8aa03f8003986a71c

glanceclient/v2/images.py

@@ -146,7 +146,7 @@ class Controller(object):
 
             tags_url_params.append({'tag': encodeutils.safe_encode(tag)})
 
-        for param, value in six.iteritems(filters):
+        for param, value in filters.items():
             if isinstance(value, six.string_types):
                 filters[param] = encodeutils.safe_encode(value)
 

glanceclient/v2/metadefs.py

@@ -60,7 +60,7 @@ class NamespaceController(object):
         :param kwargs: Unpacked namespace object.
         """
         namespace = self.get(namespace_name)
-        for (key, value) in six.iteritems(kwargs):
+        for (key, value) in kwargs.items():
             try:
                 setattr(namespace, key, value)
             except warlock.InvalidOperation as e:
@@ -174,7 +174,7 @@ class NamespaceController(object):
                 raise ValueError('sort_dir must be one of the following: %s.'
                                  % ', '.join(SORT_DIR_VALUES))
 
-        for param, value in six.iteritems(filters):
+        for param, value in filters.items():
             if isinstance(value, list):
                 filters[param] = encodeutils.safe_encode(','.join(value))
             elif isinstance(value, six.string_types):

glanceclient/v2/schemas.py

@@ -16,7 +16,6 @@
 import copy
 import json
 import jsonpatch
-import six
 import warlock.model as warlock
 
 
@@ -51,7 +50,7 @@ class SchemaBasedModel(warlock.Model):
         original = copy.deepcopy(self.__dict__['__original__'])
         new = dict(self)
         if self.schema:
-            for (name, prop) in six.iteritems(self.schema['properties']):
+            for (name, prop) in self.schema['properties'].items():
                 if (name not in original and name in new and
                         prop.get('is_base', True)):
                     original[name] = None