fix(dev-db/etcd): listen on 0.0.0.0:4001

this fixes a regression where etcd no longer listens on 127.0.0.1 and
the public ip. Fix this up because etcd needs to listen on both for user
convienence and for other cluster members to talk to it.

TODO: Add 127.0.0.1 test to ami test.
Merge pull request #170 from philips/etcd-listen-on-local

fix(dev-db/etcd): listen on 0.0.0.0:4001