Remove visual noise from xmerge

Change-Id: I74b5e30d08ade403ec35298d5c783f02b22e886a
Reviewed-on: https://gerrit.libreoffice.org/8343
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>