Clarify and fix prior consultation text

Clarify and fix prior consultation text

The prior consultation clause should applies to all disclosure
exceptions.  The list end appears to have been moved by mistake.  So
put it back.

Also, no longer suggest that predisclosure list members should consult
with the discoverer, since the discoverer is not generally known to
predisclosure list members.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>