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/utils.py

@@ -17,6 +17,7 @@
 """Utilities and helper functions."""
 
 from oslo_config import cfg
+from oslo_log import log as logging
 
 import re
 import six
@@ -24,7 +25,6 @@ import uuid
 
 
 from watcher.common.i18n import _LW
-from watcher.openstack.common import log as logging
 
 UTILS_OPTS = [
     cfg.StrOpt('rootwrap_config',