Fixed Basic optim tempest test

In this changeset, I made some fixes in order to make the
multinode test pass on the gate.

Change-Id: I2433748a78c87b15893ea69964561955b478eebd

watcher/tests/common/messaging/test_messaging_handler.py

@@ -58,7 +58,7 @@ class TestMessagingHandler(base.TestCase):
             handler.transport,
             m_target,
             [self.ENDPOINT],
-            executor='evenlet',
+            executor='eventlet',
             serializer=None,
         )