uv: float win pipe patch

Float patch to fix pipe on Windows. Original commit message:

  win: fix pipe blocking writes

  In the code path for pipe blocking writes, WriteFile is already
  posting a completion packet to the I/O completion port.
  POST_COMPLETION_FOR_REQ was causing the same request to get
  returned twice by GetCompletionStatusEx.
  Also on the same code path, we were waiting on the wrong event.

  We need to update queued_bytes and write_queue_size when a
  blocking write request completes asynchronously.

Ref: https://github.com/libuv/libuv/pull/238



Reviewed-By: Julien Gilli <julien.gilli@joyent.com>
PR-URL: https://github.com/joyent/node/pull/9179