Use more specific asserts in tests

Instead of assertTrue and assertFalse use more specific asserts.
They are compatible with Python 2.7[1] and 3.4[2]

[1]: https://docs.python.org/2.7/library/unittest.html
[2]: https://docs.python.org/3.4/library/unittest.html

Change-Id: I0e6cc33a54e35fe663e5cdf2b947053528a8775f
diff --git a/neutron/tests/tempest/api/base.py b/neutron/tests/tempest/api/base.py
index 045cca2..c4d3b48 100644
--- a/neutron/tests/tempest/api/base.py
+++ b/neutron/tests/tempest/api/base.py
@@ -577,7 +577,7 @@
         }
         body = self.list_method(**pagination_args)
         resources = self._extract_resources(body)
-        self.assertTrue(len(resources) >= len(self.resource_names))
+        self.assertGreaterEqual(len(resources), len(self.resource_names))
 
     def _test_list_pagination_iteratively(self, lister):
         # first, collect all resources for later comparison
@@ -692,7 +692,7 @@
                 self.plural_name, uri
             )
             resources_ = self._extract_resources(body)
-            self.assertTrue(page_size >= len(resources_))
+            self.assertGreaterEqual(page_size, len(resources_))
             resources.extend(reversed(resources_))
 
         self.assertSameOrder(expected_resources, reversed(resources))