py3: keep stdout as defined by pycompat in procutil According to https://docs.python.org/3/library/functions.html#open, it's not possible to use 1 as buffering argument value in binary mode. This is probably why line buffering does not work well in python3. On the other hand, sys.stdout.buffer appears to be line-buffered already on python3. So by not replacing it, there should be no behavior change. This fixes buffering issue in "hg email" (confirmation prompt shown before information to be confirmed).

notify: cast hash to bytes This is needed to avoid a str/bytes mismatch when interpolating a line or 2 later. Differential Revision: https://phab.mercurial-scm.org/D7021