D2160: py3: use b'' in inline extension

[pulkit (Pulkit Goyal)]

pulkit accepted this revision.
pulkit added a comment.


  This should be # skip-blame.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D2160

To: indygreg, #hg-reviewers, pulkit
Cc: pulkit, mercurial-devel