[Vagrantfile] skydns fixes and stuff

Make it so that the name argument to the agent is a name,
so when it gets registered in skydns it's not weird.

Also point local dns to the skydns server and register the
machine name (ubuntu-14) in it.
Merge pull request #110 from spotify/drewc/vagrant-fixen

[Vagrantfile] skydns fixes and stuff