use passed redis connection object rather than create one

[atdt]

I think it's a bit awkward and wasteful that openid-redis insists on creating a redis.Redis connection instance. Presumably, if someone is using redis for Open ID authentication, s/he is using it for other things too, so s/he is likely to already have a connection set up. I think it's neater to just require a redis client as a parameter to init.

[bbangert]

It is a bit wasteful, though there's been a decent amount of ppl using this openid store for awhile, and just completely breaking the existing API in one go seems really bad. How about retaining the existing signature to avoid breaking everyone's apps, and making it optionally take a conn argument?

[atdt]

Yes, that sounds reasonable. I've made things backwards-compatible as you suggested. I'm still learning git, so please excuse the superfluous commits .

[bbangert]

Thanks!