Trying to install a non-existent driver gives authorization error

[smola]

From src-d/sourced-ce#104 (thanks @BFergerson):

I accidentally typed the command srcd parse drivers install list instead of srcd parse drivers list and received error:

INFO[0000] installing driver                             language=list version=latest
ERRO[0000] unable to install version latest of list driver: rpc error: code = Unknown desc = can't install list driver: rpc error: code = Unknown desc = errors:
denied: requested access to the resource is denied
unauthorized: authentication required

authentication required is an odd error for this mistaken command.

[dennwc]

This error comes from the Dockerhub. We can detect it and rewrite an error message, but if you try to download a private Docker image without proper credentials, an error will be "cannot find the driver" which is also misleading. But I guess this is not a common use case right now, so overriding an error makes sense.

[smola]

@dennwc We can also make it explicit in the error, something like The driver does not exist or it is private
or maybe The driver does not exist if it is bblfsh organization and The driver does not exist or it is private otherwise.

[bzz]

Fixed in #213