Try to enable IPv6 on travis.
Try to enable IPv6 on travis.

dsanders11/rtpproxy,synety-jdebp/rtpproxy,jevonearth/rtpproxy,sippy/rtpproxy,dsanders11/rtpproxy,jevonearth/rtpproxy,synety-jdebp/rtpproxy,dsanders11/rtpproxy,sippy/rtpproxy,sippy/rtpproxy,jevonearth/rtpproxy,synety-jdebp/rtpproxy,jevonearth/rtpproxy,synety-jdebp/rtpproxy