* git rev-parse --show-toplevel doesn't work inside git dir.
* Only "Describe (show)" should be available for those files. show
  works when running from inside the git dir

Change-Id: If5f3d1af8da2f8d149ac1e03ffd70b530e609557
Reviewed-by: Petar Perisin <petar.perisin@gmail.com>
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>