Explicit re-raise the BufferError exception in recv from the orignal
JSONDecodeError, so the latter gets recorded as the underlying cause.
Uncovered by pylint 2.6.0: W0707: "Not using raise from makes the
traceback inaccurate, because the message implies there is a bug in
the exception-handling code itself, which is a separate situation
than wrapping an exception."
cd1f248dca