httputil fails randomly on node 0.6

tests that use httputil fail at random on 0.6

node.js:201
throw e; // process.nextTick error, or 'error' event on first tick
^
Error: connect ECONNREFUSED
at errnoException (net.js:616:11)
at Object.afterConnect [as oncomplete](net.js:607:18)

Locate the tests that use httputil and first try to reproduce the intermittent ECONNREFUSED failure on Node.js 0.6. Trace which connection or server setup is involved and check whether the failure can be made deterministic. Done means the httputil tests run reliably without random connection refusals.

索引モデルが issue の本文から書いたものです。