mailer.py: Followup changes, fixing some bugs in the Win32 compatibility code, and also return to passing the stderr of diff programs into the email.
mailer.py: Followup changes, fixing some bugs in the Win32 compatibility code,
and also return to passing the stderr of diff programs into the email.

* tools/hook-scripts/mailer/mailer.py: Improve the Popen3 compat class, and add
    a Popen4 version.
  (OutputBase.run): Use Popen4, not Popen3.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@852616 13f79535-47bb-0310-9956-ffa450edef68

wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion