improve error message when dock.sock is unavailable

[lucasbalieiro]

during the setup process (IPC validation), if the communication with docker.sock fails we get an ugly error:

[GitGab19]

Shouldn't this be related to #144 as well?

[lucasbalieiro]

Shouldn't this be related to #144 as well?

humm, probably duplicated. Gonna check it later today. tahnks