maint: update copyright paper procedures
Requested by Donald R. Robertson III via gnu.org ticket #
1028294.
* config/srclist.txt: Drop outdated files.
* doc/Copyright/conditions.txt: Update to latest.
* doc/Copyright/assign.changes.manual: Delete.
* doc/Copyright/assign.future.manual: Likewise.
* doc/Copyright/assign.manual: Likewise.
* doc/Copyright/assign.translation.manual: Likewise.
* doc/Copyright/disclaim.changes.manual: Likewise.
* doc/Copyright/disclaim.manual: Likewise.
* doc/Copyright/disclaim.program: Likewise.
Signed-off-by: Eric Blake <eblake@redhat.com>