[PATCH 1 of 6 STABLE V2] make: turn ubuntu docker into template

[Augie Fackler]

> On Apr 29, 2016, at 13:20, Sean Farley <sean at farley.io> wrote:
> 
>> The make way would be to depend on real files, but I don't care much about it
>> since our Makefile is full of phony rules.
>> 
>> contrib/docker/ubuntu-%: contrib/docker/ubuntu.template
>> 	sed "s/__CODENAME__/$*/" $< > $@
>> 
>> docker-ubuntu-trusty: contrib/docker/ubuntu-trusty
>> 	contrib/dockerdeb ubuntu trusty
> 
> Ah, that looks a little better. I'll test it out.

Excellent. I was going to suggest this change anyway. :)