Reference dogpile.cache.memcached backend properly

It is dogpile.cache.memcached, not dogpile.cache.memcache
see
http://dogpilecache.readthedocs.org/en/latest/api.html?highlight=memcache#module-dogpile.cache.backends.memcached

Change-Id: Ia2aded1be82453b87a7734441537a5976385616e
reverse my preferred mailmap

there's too many mailing lists at work

Change-Id: I0521f02ecf6fc81afa0ec29c96e86c68795a2218
Merge "reverse my preferred mailmap"
Merge "Reference dogpile.cache.memcached backend properly"