fdo#75206: use 'ne' for string comparison

Change-Id: I0d059933786119c3c26202c7b48d793404e5a0eb
Reviewed-on: https://gerrit.libreoffice.org/8129
Reviewed-by: Michael Stahl <mstahl@redhat.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>