Use olso.log directly

As the openstack/common is deprecated, Watcher should use oslo lib
directly to run in the openstack env. So there is much work to do
with oslo. This patch fixed the log part.

Change-Id: I3145a842fe3a22b3d08fec60d180329073edd50f

watcher/common/messaging/messaging_handler.py

@@ -16,13 +16,13 @@
 
 import eventlet
 from oslo_config import cfg
+from oslo_log import log
 import oslo_messaging as om
 from threading import Thread
 from watcher.common.messaging.utils.transport_url_builder import \
     TransportUrlBuilder
 from watcher.common.rpc import JsonPayloadSerializer
 from watcher.common.rpc import RequestContextSerializer
-from watcher.openstack.common import log
 
 eventlet.monkey_patch()
 LOG = log.getLogger(__name__)