refactor(etcd): Gather etcd-related code in etcd pkg
fix(go-etcd): Close response bodies

This is a hack roughly equivalent to go-etcd commit
2df4f0d2729c5ca94955b44604a87929306e2ace
Merge pull request #509 from bcwaldon/go-etcd-hack

fix(go-etcd): Close response bodies
fix(go-etcd): Replace deferred response body close
fix(go-etcd): close response body before continue
Merge pull request #511 from bcwaldon/replace-defer

Ensure go-etcd calls resp.Body.Close()
Merge pull request #508 from bcwaldon/etcd-pkg

Gather etcd-related code in etcd pkg
feat(fleetctl): add template unit support to fleetctl start/submit