Fix bug in ultra provider tests when run in Python 2.7

The test_login test from TestUltraProvider would fail in Python 2.7
due to the dictionary insertion order not being preserved in 2.7
and early 3.x versions. Comparing the dictionaries containing the
query parameters solves this. Snippet from test failure:

- username=user&password=rightpass&grant_type=password
+ grant_type=password&username=user&password=rightpass

tests/test_octodns_provider_ultra.py

@@ -1,3 +1,12 @@
+from __future__ import unicode_literals
+
+try:
+    # Python 3
+    from urllib.parse import parse_qs
+except ImportError:
+    # Python 2
+    from urlparse import parse_qs
+
 from mock import Mock, call
 from os.path import dirname, join
 from requests import HTTPError
@@ -55,7 +64,8 @@ class TestUltraProvider(TestCase):
             self.assertEquals(1, mock.call_count)
             expected_payload = "grant_type=password&username=user&"\
                                "password=rightpass"
-            self.assertEquals(mock.last_request.text, expected_payload)
+            self.assertEquals(parse_qs(mock.last_request.text),
+                              parse_qs(expected_payload))
 
     def test_get_zones(self):
         provider = _get_provider()