rename /usr/sbin/setup to avoid accidentally running legacy UI

previously we sym-linked the ovirt-config-setup (slang/newt UI)
in /usr/sbin so it could be run by simply running setup.

We don't want people to accidentally run the legacy UI if we can
avoid it, so change this symlink to point to the urwid based UI.

Change-Id: I5cf0862871ab762dd80b2a9b135ad8fbe44b7347
Signed-off-by: Mike Burns <mburns@redhat.com>