D7005: py3: manually import pycompat.open into files that need it

[durin42 (Augie Fackler)]

durin42 added a comment.


  In D7005#102780 <https://phab.mercurial-scm.org/D7005#102780>, @martinvonz wrote:
  
  > Can we import `io.open` regardless of Python version instead?
  
  That won't work because pycompat.open accepts bytestrings as the mode argument. I'll take this now, and then we can do a cleanup to unwind the mode string back to a sysstr everywhere (I'll take that on if Pulkit doesn't).

REPOSITORY
  rHG Mercurial

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  https://phab.mercurial-scm.org/D7005/new/

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  https://phab.mercurial-scm.org/D7005

To: indygreg, durin42, martinvonz, #hg-reviewers
Cc: mercurial-devel