Allow expiring sandbox keys in the RedisResource.
Override txredis.ttl() to return None when the return value is < 0 (like sync redis does).
I cannot un-see the parameters of setex.
The situation is even crazier than I thought, O_o.
Fix grammar.
Require redis 2.7.1 or better (older redis versions have a different behaviour for ttl).
Merge branch 'feature/issue-860-expire-all-the-things' of github.com:praekelt/vumi into feature/issue-860-expire-all-the-things
Switch fake redis to always use setex(key, time, value).
Wrap sync redis .setex() and give it the same signature as the txredis .setex().
Merge branch 'feature/issue-860-expire-all-the-things' into develop