make validate repaired via a temporary fix for #2949

 I simply provide an explicit argument to one of the functors, avoiding
 the faulty use of the "include-to-self" feature there.
 Note that this NZOrderedType functor could also be simply removed
 as in trunk, since it isn't used anywhere.

 Btw, the Not_found in coqchk is now turned into something slightly
 more informative.

 The core of the bug remains: coqtop should check that "include-to-self"
 hasn't produced a chimera (more details in the bug tracker).

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/branches/v8.4@16201 85f007b7-540e-0410-9357-904b9bb8a0f7