Port cookbook to Grizzly

Previously we where doing a lot of things which had little to do with
what happened during the last year. For instance, keystone auth values
moved from /etc/glance/glance-*-api-paste.ini to
/etc/glance/glance-*.conf (thus adjusting previously broken file perms).
Theremore, most upstream paste.ini files can be used as is (yay!).
glance-pruner/prefetcher/reaper went the way of the dodo.

Further glance fixes will very likely have to depend on this.

I'll do some more tests on this one, this pull is for getting the review / testing started.