File _servicedata of Package libbacktrace

<servicedata>
  <service name="tar_scm">
    <param name="url">https://github.com/ianlancetaylor/libbacktrace.git</param>
    <param name="changesrevision">0034e33946824057b48c5e686a3aefc761b37384</param>
  </service>
</servicedata>