Further problems with systemd-resolved on xubuntu 17.04

[Chris Green]

> 
> I don't know why you would have a fallback DNS in any case.
> 
> You could remove it?
> 
Yes, I could, but guest users on my network can't access the local DNS
server (they only have access to the outside world) but they *do* get
DHCP services from the local server (an oddity of the firewall).  Thus
they need a fallback DNS that will work for them, that's why I added
it.

-- 
Chris Green