regression from...

commit 9b77f814
Author: Caolán McNamara <caolanm@redhat.com>
Date:   Thu Apr 6 15:08:45 2017 +0100

    ditch ReadRawUniString

three argument lclGetString32 variant mistaken for two argument lclGetString32
variant

Change-Id: I163aad0de7873487d9f9c8b6c28d162159fe7ad4
Reviewed-on: https://gerrit.libreoffice.org/61887
Tested-by: Jenkins
Reviewed-by: Xisco Faulí <xiscofauli@libreoffice.org>