docker_registry.index: Remove local logger

This was added in d2ace65 (Naive mirroring implementation,
2014-02-06) in support of some
/v1/repositories/<path:repository>/images logging.  Those logs were
removed in bbb487a (Using mirroring decorator on index route,
2014-03-07), but this code was left behind.

Author: wking

docker_registry/index.py

@@ -1,7 +1,5 @@
 # -*- coding: utf-8 -*-
 
-import logging
-
 import flask
 import flask_cors
 
@@ -18,7 +16,6 @@
 
 
 store = storage.load()
-logger = logging.getLogger(__name__)
 
 """Those routes are loaded only when `standalone' is enabled in the config
    file. The goal is to make the Registry working without the central Index