unotest: the assigned value is never used

Change-Id: I73c4945dec1db4c206948f27ba3d19fa08eedd46
Reviewed-on: https://gerrit.libreoffice.org/11742
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>