Testing metafora's Etcd client requires integration tests.

[mdmarek]

Currently the only tests for metafora's etcd client-functions require that an instance of etcd actually be running. Somehow this either needs to happen automatically, maybe we can start etcd programatically, or convert the the tests to use some kind of stand-in for etcd.

[epsniff]

We'll need to do the latter because Travis CI isn't going to stand up an EtcD cluster for us to use :(