SetText was addes as seen in other dialogs, for completeness,
although all call places seem to pass the default null pointer.

Change-Id: I1fe1792ad6f061fc762bae237f5cecfcbbd1ce06
Reviewed-on: https://gerrit.libreoffice.org/5616Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>