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

Co-Authored-By: Akihiro Motoki <amotoki@gmail.com>
Change-Id: I4b9edb326444264c0f6c4ad281acaac356a07e85
Implements: blueprint replace-iteritems-with-items

openstackclient/compute/v2/keypair.py

@@ -23,7 +23,6 @@ import sys
 from osc_lib.command import command
 from osc_lib import exceptions
 from osc_lib import utils
-import six
 
 from openstackclient.i18n import _
 
@@ -101,7 +100,7 @@ class CreateKeypair(command.ShowOne):
                 del info['public_key']
             if 'private_key' in info:
                 del info['private_key']
-            return zip(*sorted(six.iteritems(info)))
+            return zip(*sorted(info.items()))
         else:
             sys.stdout.write(keypair.private_key)
             return ({}, {})
@@ -184,7 +183,7 @@ class ShowKeypair(command.ShowOne):
         info.update(keypair._info)
         if not parsed_args.public_key:
             del info['public_key']
-            return zip(*sorted(six.iteritems(info)))
+            return zip(*sorted(info.items()))
         else:
             # NOTE(dtroyer): a way to get the public key in a similar form
             #                as the private key in the create command