Moved dependency management from govendor to dep

[rugwirobaker]

after encountering some challenges while trying to add go.etcd.io/etcd, I decided to move from govendor (dep)[https://github.com/golang/dep] after having consulted with the etcd project (https://github.com/etcd-io/etcd/issues/10288#issue-385597736) and realizing the issue was with the dependency manager. Then after I was asked to open a PR (https://github.com/nanopack/shaman/issues/39#issuecomment-443217139)

[rugwirobaker]

I think some test previously ghosted because govendor returned with code 0 even for failed tests while go test doesn't so the tests won't pass until we install a postgres agent om which to make test like it was done with consul.

[rugwirobaker]

I think this here will do https://docs.travis-ci.com/user/database-setup/#postgresql

[tylerflint]

This is shaping up! I don't think we want to do dep ensure -update. The dependencies should be checked in to the project anyway, but a dep ensure should do the trick.

[rugwirobaker]

I had first to bump the go version to go1.11.1 the same on my local environment. github.com/miekg/dns was giving me all sorts of problems.

[rugwirobaker]

However I am going to try and add redis before I try etcd which is more complex, then after I ahve understood the whole codebase I can try etcd