Re: [PATCH jk/pkt-line-cleanup] t5700-clone-reference: send trace to fd 2, not 3, to please Windows git

Jeff King [off-list ref] writes:

Also, though I think your use of stderr is probably OK, might it be a
little more robust against future output changes to use:

  GIT_TRACE_PACKET=$PWD/$U.D git clone ...

to write directly to the file. The original GIT_DEBUG_SEND_PACK did not
support such niceties, but GIT_TRACE gives them to us for free.

Sounds very sensible.