Merge pull request #932 from pmoura/fix_abolish_bug_with_no_existing_predicates

Fix abolish/1 to succeed on non-existing predicates as per standard

src/lib/builtins.pl

@@ -1035,6 +1035,8 @@ module_abolish(Pred, Module) :-
           ;  functor(Head, Name, Arity) ->
              (  '$head_is_dynamic'(Module, Head) ->
                 '$abolish_clause'(Module, Name, Arity)
+             ;  '$no_such_predicate'(Module, Head) ->
+                true
              ;  throw(error(permission_error(modify, static_procedure, Pred), abolish/1))
              )
           )