Build is failing on Travis CI due to change in host name resolution

[xkrogen]

Master started failing as of Travis Build #76 on 2018-10-05. Build #75 on 2018-09-28 was fine, and no commits went in between the two.

[xkrogen]

As far as I can tell this is because something on Travis CI infrastructure changed in such a way that the host name resolution doesn't work properly anymore; the client was getting "Connection Refused" when attempting to talk to the DataNodes.