Use fakeroot to call tar when creating the tar.gz archives
holding the desktop-integration parts to have root:root
as owner of the files inside those.

Change-Id: Idcdcb4dd398f330773671266dafb354711b0f093
Reviewed-on: https://gerrit.libreoffice.org/49827Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>