Fix of https://s3.amazonaws.com/archive.travis-ci.org/jobs/36965919/log.txt

privileged.c:1059:35: error: â€˜sigset_oldâ€™ undeclared (first use in this function)
privileged.c:1059:35: note: each undeclared identifier is reported only once for each function it appears in
Added libkqueue-dev to apt-get list in .travis.yml