Bug 1100905 — Remove redis keys wildcard lookups.
@mikedeboer review.
Rename the credentials var into metadata on /.
Rename redis "roomparticipant" to "roomparticipants".

In addition to being cleaner, this will help have two different namespaces for
the participants lists (one for 0.13.2 and one for after).
Merge pull request #254 from mozilla-services/1100905-participant-redis-hashes

Bug 1100905 — Remove redis keys wildcard lookups.
Merge pull request #256 from mozilla-services/rename-homepage-credentials

Rename the credentials var into metadata on /.
Merge master