Fix filter names for redis.
Fix filter names for redis.

We were using "val" everywhere which doesn't convey any meaning, we are now
using the type of the list we're manipulating (call, url, room).

mozilla-services/loop-server,kitcambridge/loop-server,magopian/loop-server,kitcambridge/loop-server,magopian/loop-server,mozilla-services/loop-server