Check for a foreign key, not a constraint.

inst/upgrade/1.6.10/fix_asset_desk_constraints.pl

@@ -11,7 +11,7 @@
         FROM   pg_class c, pg_constraint r
         WHERE  r.conrelid = c.oid
                AND c.relname = 'story'
-               AND r.contype = 'c'
+               AND r.contype = 'f'
                AND r.conname = 'fk_desk__story'
 };