remove unused LOG

This is to remove unused LOG to keep code clean

Change-Id: Iba4e29892f3011356ce927f73ce9f418365df609

tackerclient/common/clientmanager.py

@@ -17,15 +17,10 @@
 """Manage access to the clients, including authenticating when needed.
 """
 
-import logging
-
 from tackerclient import client
 from tackerclient.tacker import client as tacker_client
 
 
-LOG = logging.getLogger(__name__)
-
-
 class ClientCache(object):
     """Descriptor class for caching created client handles."""