Remove visual noise from sdext

Change-Id: I792249b9e92db9af4daee0bd835e04044d29bca5
Reviewed-on: https://gerrit.libreoffice.org/8308
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>