D5199: test: fix self._testdir to use ues the right mercurial library during testing

[sangeet259 (Sangeet Kumar Mishra)]

sangeet259 added a comment.


  @yuja 
  This passes the tests now. I had missed the subsequent code that was dependent on the earlier initialisation of `self._testdir`.
  Fixed it.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D5199

To: sangeet259, #hg-reviewers
Cc: yuja, mercurial-devel