Fix calls to mock.assert_not_called()

There is no assert_not_called() method in mock, as described here:
https://code.google.com/p/mock/issues/detail?id=159
Fix these calls to use the assertEqual(0, mock.call_count) instead.
This patch also fixes a typo.

Change-Id: I7cfb968f6d4b775ceb901411ee8f24057d97cf91
diff --git a/tempest/tests/test_ssh.py b/tempest/tests/test_ssh.py
index 0da52dc..48d2fd2 100644
--- a/tempest/tests/test_ssh.py
+++ b/tempest/tests/test_ssh.py
@@ -36,13 +36,13 @@
             rsa_mock.assert_called_once_with(mock.sentinel.csio)
             cs_mock.assert_called_once_with('mykey')
             rsa_mock.reset_mock()
-            cs_mock.rest_mock()
+            cs_mock.reset_mock()
             pkey = mock.sentinel.pkey
             # Shouldn't call out to load a file from RSAKey, since
             # a sentinel isn't a basestring...
             ssh.Client('localhost', 'root', pkey=pkey)
-            rsa_mock.assert_not_called()
-            cs_mock.assert_not_called()
+            self.assertEqual(0, rsa_mock.call_count)
+            self.assertEqual(0, cs_mock.call_count)
 
     def _set_ssh_connection_mocks(self):
         client_mock = mock.MagicMock()
@@ -75,7 +75,7 @@
             password=None
         )]
         self.assertEqual(expected_connect, client_mock.connect.mock_calls)
-        s_mock.assert_not_called()
+        self.assertEqual(0, s_mock.call_count)
 
     def test_get_ssh_connection_two_attemps(self):
         c_mock, aa_mock, client_mock = self._set_ssh_connection_mocks()