Adds assertIn and assertNotIn support to TestCase for compatibility with python 2.6

This is a very minimal addition which doesn't require unittest2.

nova/test.py

@@ -277,3 +277,21 @@ class TestCase(unittest.TestCase):
                 continue
             else:
                 self.assertEqual(sub_value, super_value)
+
+    def assertIn(self, a, b, *args, **kwargs):
+        """Python < v2.7 compatibility.  Assert 'a' in 'b'"""
+        try:
+            f = super(TestCase, self).assertIn
+        except AttributeError:
+            self.assertTrue(a in b, *args, **kwargs)
+        else:
+            f(a, b, *args, **kwargs)
+
+    def assertNotIn(self, a, b, *args, **kwargs):
+        """Python < v2.7 compatibility.  Assert 'a' NOT in 'b'"""
+        try:
+            f = super(TestCase, self).assertNotIn
+        except AttributeError:
+            self.assertFalse(a in b, *args, **kwargs)
+        else:
+            f(a, b, *args, **kwargs)