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 * config/srclist.txt: Drop outdated files.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>