Fix incorrect initialization of OrderedDict

According to the doc[1], initialize OrderedDict as below won't
perserve the order:

  collections.OrderedDict({...})

This causes occasional failures of the tests. This patch changed it
to:

  collections.OrderedDict([...])

[1] https://docs.python.org/3/library/collections.html#
ordereddict-objects

Change-Id: I863f9d2879a6c119501fe1d5175ecb8a70e7e9f1
Closes-Bug: #1556475

magnumclient/tests/test_utils.py

@@ -187,15 +187,18 @@ class CliUtilsTest(test_utils.BaseTestCase):
                                 six.u('z'): six.u('3')},
                    'c': 7}
 
-        dict_exp = collections.OrderedDict(
-            {'a': '1',
-             'b': collections.OrderedDict({'x': 1, 'y': '2', 'z': '3'}),
-             'c': 7})
+        dict_exp = collections.OrderedDict([
+            ('a', '1'),
+            ('b', collections.OrderedDict([
+                ('x', 1),
+                ('y', '2'),
+                ('z', '3')])),
+            ('c', 7)])
 
         dict_out = cliutils.keys_and_vals_to_strs(dict_in)
-        dict_act = collections.OrderedDict(
-            {'a': dict_out['a'],
-             'b': collections.OrderedDict(dict_out['b']),
-             'c': dict_out['c']})
+        dict_act = collections.OrderedDict([
+            ('a', dict_out['a']),
+            ('b', collections.OrderedDict(sorted(dict_out['b'].items()))),
+            ('c', dict_out['c'])])
 
         self.assertEqual(six.text_type(dict_exp), six.text_type(dict_act))