45be775ebf
In a running proxy server, this only ever comes from one place:
a key in the wsgi env, populated by the memcache middleware. By
littering proxy controller code with things like
memcache = getattr(app, 'memcache', None) or env.get('swift.cache')
we cause ourselves to second-guess that.
Change-Id: Ia652b1381990b61194978c4efaebac7d2a602ca3