The cause message doesn't include the host the error occurred on.
Before:
```
$ mrsk deploy
Acquiring the deploy lock...
Finished all in 0.1 seconds
ERROR (SocketError): getaddrinfo: nodename nor servname provided, or not known
```
After:
```
$ mrsk deploy -d staging
Acquiring the deploy lock...
Finished all in 0.1 seconds
ERROR (SocketError): Exception while executing on host server-123: getaddrinfo: nodename nor servname provided, or not known
```
