drop xFocusWin hack, I don't see what gain it gives

Change-Id: I31952b5440797e6209ed1de6b546f1e4c0238d08
Reviewed-on: https://gerrit.libreoffice.org/71675
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>