Do nothing for numbers 0x00 - 0x1f.

Change-Id: Idda596e735c464b97dc3624253ebbea86933ff2c
Reviewed-on: https://gerrit.libreoffice.org/19654Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>