message: Add apt-key for ubuntu keyserver
diff: @@ -28,6 +28,7 @@ if [[ "$1" != "" ]] && [[ "$1" != "--without_cmake" ]]; then
  fi
  # Install dependencies from ubuntu deb repository.
  +apt-key adv --keyserver keyserver.ubuntu.com --recv 084ECFC5828AB726
  apt-get update
  if [[ "$ubuntu_version" == "14" ]]; then
  