gcrypt import warnings

[Robert Vollmert]

I’m getting the following warnings when running “make” in the guix repo:

WARNING: (guix scripts archive): `error-source' imported from both (gcrypt 
common) and (gcrypt pk-crypto)
WARNING: (guix scripts archive): `error-string' imported from both (gcrypt 
common) and (gcrypt pk-crypto)

Presumably introduced by the commit below; what was the reason for
the change?

commit 92ca25a32b4bd19cda563fa0807af0fa2d39e0e2
Author: Ludovic Courtès <address@hidden>
Date:   Fri Jul 19 11:38:54 2019 +0200

    guix archive: Use (gcrypt common).
    
    * guix/scripts/archive.scm: Use (gcrypt common) for 'error-source' and
    'error-string'.