I found out the hard way that, despite the Celery docs saying it will
respect settings of "none", "required", etc for the ssl_cert_reqs option
on ths broker connection uri, one it's underlying dependencies does not.
That dependency, Kombu, requires that the option be set as the string
version of one of the constants available on the standard library's ssl
module ("CERT_NONE", etc.). This fixes our code to supply slightly
variant connection URIs for Celery and for the session library. This
change can be reverted when Kombu is updated with the correct behavior.
788f73b7a9