Define the namespace near the element that's using it

Change-Id: If0a135a331d4f67ef2dfe4981e93110e7a1a787a
Reviewed-on: https://gerrit.libreoffice.org/40084Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>