Bug#891278: ntpsec-ntpviz: fails to install: install: invalid user 'ntp'

[Richard Laager]

Since ntpsec-ntpviz does not Depend, much less Pre-Depend, on ntpsec, the 
adduser from ntpsec.postinst needs to be duplicated into ntpsec-ntpviz.postinst.

I’ll take care of this in a couple days.

-- 
Richard