Keep up with v2.

Changes to the v2 API (v2.x?) broke both etcd_get for directory
listings and etcd_watch.

Signed-off-by: Jeff Darcy <jdarcy@redhat.com>
Change etcd-test syntax.

The old syntax was getting a bit too arcane.  This way should make it
easier to add new functions, such as (momentarily) etcd_lock.

Signed-off-by: Jeff Darcy <jdarcy@redhat.com>