Remove the consideration of a sort_limit when deciding on a the sort …

…index scan. If the sort index is a lot smaller than the result set, N-Best/N-Worst algorithms won't do any better

src/Products/ZCatalog/Catalog.py

@@ -729,11 +729,9 @@ def sortResults(self, rs, sort_index, reverse=False, limit=None,
                 sort_spec.append(reverse and -1 or 1)
             first_reverse = reverse
 
-        if merge and limit is None and (
-            rlen > (len(sort_index) * (rlen / 100 + 1))):
+        if merge and (rlen > (len(sort_index) * (rlen / 100 + 1))):
             # The result set is much larger than the sorted index,
             # so iterate over the sorted index for speed.
-            # This is rarely exercised in practice...
             length = 0
             try:
                 intersection(rs, IISet(()))