Switch Debian 3rdparty packages to our OBS repo (https://build.opensuse.org/project/subprojects/home:scylladb). We don't use 3rdparty packages on dist/debian/dep, so dropped them. Also we switch Debian to gcc-7.2/boost-1.63 on same time. Due to packaging issues following packages doesn't renamed our 3rdparty package naming rule for now: - gcc-7: renamed as 'xxx-scylla72', instead of scylla-xxx-72. - boost1.63: doesn't renamed, also doesn't changed prefix to /opt/scylladb Message-Id: <1510952411-20722-1-git-send-email-syuu@scylladb.com>