due to various clients and the existence of rpcd-mod-rpcsys the package
rpcd-mod-attendedsysupgrade is superflous.

From now on the attendedsysupgrade-common package should be dependencie
of all kinds of clients.

Currently active or planned:
- luci-app-attendedsysupgrade
- attendedsysupgrade cli in shell
- attendedsysupgrade cli in c

Signed-off-by: Paul Spooren <paul@spooren.de>