Use CONF for oslo_config's cfg.CONF again

In most OpenStack projects, the instance of oslo_config's cfg.CONF
is declared as CONF. This patch applies it for readability on whole
OpenStack components.

NOTE: The commit I7758a1ce86de8689fb2c5e420e042fa56c275927 missed
      a few places and this patch covers them. Sorry for this mess.

Change-Id: I1a20ea8b4b7092fd8ed565f8020dbb65c39b9cf1

stackalytics/dashboard/web.py

@@ -674,7 +674,7 @@ def timeline(records, **kwargs):
 
 @app.template_test()
 def too_old(timestamp):
-    age = cfg.CONF.age_warn
+    age = CONF.age_warn
     now = time.time()
     return timestamp + age < now
 

stackalytics/processor/utils.py

@@ -125,7 +125,7 @@ def _session_request(session, uri, method):
 
     headers = {'User-Agent': user_agent, 'Accept': 'application/json'}
     return session.request(method, uri, headers=headers,
-                           timeout=cfg.CONF.read_timeout)
+                           timeout=CONF.read_timeout)
 
 
 def do_request(uri, method='get', session=None):