Log Message:
py-supervisor: updated to 4.2.1

4.2.1

- Fixed a bug on Python 3 where a network error could cause ``supervisord``
  to crash with the error ``<class 'TypeError'>:can't concat str to bytes``.
  Patch by Vinay Sajip.

- Fixed a bug where a test would fail on systems with glibc 2.3.1 because
  the default value of SOMAXCONN changed.