spack:/etc/dbus-1/system.d# more skype.conf
<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>

  <!-- ../system.conf have denied everything, so we just punch some holes -->

  <policy context="default">
    <allow own="com.Skype.API"/>

    <allow send_destination="com.Skype.API"/>
    <allow receive_sender="com.Skype.API"/>

    <allow send_path="/com/Skype"/>
  </policy>

</busconfig>