Remove unnecessary env vars carried over from when this was a standalone CLI

[ctlong]

LOG_CACHE_ADDR and LOG_CACHE_SKIP_AUTH seem unnecessary now that this code is not published as an independent CLI anymore. I think we can remove them and instead just assume that the Log Cache address of the CF instance the cf CLI is targeting can be used.

[ctlong]

Doesn't seem like anyone is opposed, so I'm going to do this at some point.