fdo#81552 Fail nicely if avahi doesn't let libreoffice publish items

Change-Id: Ie264a032a71bda336158e18bd2b14c569f23f42d
Reviewed-on: https://gerrit.libreoffice.org/10735
Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>