* guix/scripts/package.scm (delete-generations): Use
'delete-generation*' instead of 'delete-generation'.
(guix-package)[process-actions]: Use 'roll-back*' instead of
'roll-back' and 'switch-to-generation*' instead of
'switch-to-generation'.
(link-to-empty-profile, switch-to-generation,
switch-to-previous-generation, roll-back, delete-generation): Move
to...
* guix/profiles.scm: ... here. Adjust to not print messages and to
return values that can be used by user interfaces.
* guix/ui.scm (display-generation-change, roll-back*,
switch-to-generation*, delete-generation*): New procedures.
06d45f4566