Uninformative error message if Docker is not installed

[marmistrz]

gu-client shows: (see #236)

bad response 500 Internal Server Error

gu-hub shows:

ERROR 2019-07-16T08:24:44Z: actix_web::pipeline: Error occurred during request handling, status: 500 Internal Server Error Cannot create peer deployment

gu-provider prints (on debug only!!)

DEBUG 2019-07-16T08:24:44Z: gu_net::rpc::ws: emit message: EmitMessage { dest_node: 0x68fa6405d4905c26aa7a497b4172353bc62f30df, destination: [171, 3, 172, 80, 96, 66, 163, 184], correlation_id: Some([255, 173, 192, 205, 229, 151, 233, 99]), reply_to: None, ts: 0, expires: None, body: Reply("{\"Err\":{\"IoError\":\"error trying to connect: No such file or directory (os error 2)\"}}") }

neither of these messages is informative.

[github-actions[bot]]

Stale issue message

[filipgolem]

Some initial fixes in 15e950a586609876e760cbe6ae2d79f86067be01

[github-actions[bot]]

Stale issue message