Fixed PR 478 -- Removed superfluous try/except block.

django/db/models/query.py

@@ -209,12 +209,10 @@ class QuerySet(object):
                 stop = None
             qs.query.set_limits(start, stop)
             return k.step and list(qs)[::k.step] or qs
-        try:
+
         qs = self._clone()
         qs.query.set_limits(k, k + 1)
         return list(qs)[0]
-        except self.model.DoesNotExist as e:
-            raise IndexError(e.args)
 
     def __and__(self, other):
         self._merge_sanity_check(other)