chore(*): rely on etcdctl in deis/base

As of deis/base#4, etcdctl v0.4.2 includes the --no-sync option.
We no longer need to install an etcdctl branch just to get this
option.
Merge pull request #1163 from deis/remove-etcdctl

chore(*): rely on etcdctl in deis/base
chore(builder): rely on deis/base to manage confd

Please test this PR in conjunction with deis/base#3