We monkey patch Kombu's entrypoints listing because scanning through
this accounts for the majority of LMS/Studio startup time for tests,
and we don't use custom Kombu serializers (which is what this is for).
Still, this is pretty evil, and should be taken out when we update
Celery to the next version where it looks like this method of custom
serialization has been removed.

FWIW, this is identical behavior to what happens in Kombu if
pkg_resources isn't available.