error return code when no agent available

[Daniel Kahn Gillmor]

On Thu 2017-11-30 15:57:42 +0100, Werner Koch wrote:
> The return codes from gpg have no specific meaning.  For scripting you
> need to look at the status lines.  GPGME entirely ignores the return
> codes.

Perhaps we could invest the return codes with some specific meaning?

There are many scenarios in UNIX where return codes are expected to be 0
when an standard operation succeeds.  It's unusual to not folow that
convention.

      --dkg