bump zookeeper from 3.4.5 to 3.4.6

depends on zookeeper 3.4.6 from Godeps:
  github.com/samuel/go-zookeeper/zk 4a222ca51b4c7ca6f2895e0e68af2e9254acfdcc
from:
  https://github.com/control-center/serviced/pull/1364