D2988: fix: use a portable python script instead of sed in test

[hooper (Danny Hooper)]

hooper added a comment.


  In https://phab.mercurial-scm.org/D2988#48864, @mharbison72 wrote:
  
  > I'm not sure what the state of this is (`hg phabread` failed for 3022 and 3023), but this works on Windows.  I've got a separate patch to fix the printfs (which doesn't help the {rootpath} issue I mentioned).
  
  
  The other revisions were phabsend mistakes, I closed them.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D2988

To: hooper, #hg-reviewers
Cc: durin42, mharbison72, mercurial-devel