File _servicedata of Package libbacktrace

<servicedata>
  <service name="tar_scm">
    <param name="url">https://github.com/ianlancetaylor/libbacktrace.git</param>
    <param name="changesrevision">7e2b7da3d6568d2e4e78658f22e701746a48d7e1</param>
  </service>
</servicedata>