Fix upgrade that doesn't set the CATTLE_AGENT_IP
Set image version to master
Fix upgrade behavior to maintain env vars properly
Cattle version 0.6.0
Made startup error dynamic.

There is also situations where /var/run/docker.sock is not
read / writable by the container. This will result in a
permission denied error.
Merge pull request #21 from cloudnautique/better_error_message

Made startup error dynamic.
Cattle v0.7.0