Don't use PasteDeploy for scrubber and cache daemons

There are no WSGI apps involved here, no need to configure pipelines with
filters etc. All we're using PasteDeploy for is to construct an object.

Well ... there are easier ways to do that! :)

Change-Id: I4166d0071738fe587572db8f2883900408e9f097

glance/store/scrubber.py

@@ -88,10 +88,6 @@ class Scrubber(object):
 
         store.create_stores()
 
-    @classmethod
-    def factory(cls, global_conf, **local_conf):
-        return cls()
-
     def run(self, pool, event=None):
         now = time.time()