Add note for BF users redirected to upgrade page 

As highlighted by thread in the users mailing list (http://lists.openmicroscopy.org.uk/pipermail/ome-users/2013-October/003978.html) - people using BF command line tools outside of an OMERO setting can end up being redirected to this page, which is no help to them whatsoever!

See PR ? for corresponding addition to BF docs.