don't wrap the sentinal value :nocache in a tuple

Author: zachdaniel

lib/ecto/query/planner.ex

@@ -136,7 +136,7 @@ defmodule Ecto.Query.Planner do
   def query(query, operation, cache, adapter, counter, query_cache?) do
     {query, params, key} = plan(query, operation, adapter)
     {cast_params, dump_params} = Enum.unzip(params)
-    key = if query_cache?, do: {key, counter}, else: :nocache
+    key = if query_cache? and key != :nocache, do: {key, counter}, else: :nocache
     query_with_cache(key, query, operation, cache, adapter, counter, cast_params, dump_params)
   end