Fetching external tarball for Apache ODF Toolkit, configuration of
wrapper script for odf validator execution

Change-Id: I8b3824a91ebc6ddc196416e197b6c688964a13a9
Reviewed-on: https://gerrit.libreoffice.org/26596Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>