Ensure the rrl object is set to NULL after it is freed
Ensure the rrl object is set to NULL after it is freed

Once we free the rrl object we should NULL it to prevent a dangling ref
to it. Otherwise we could get a double free.

Reviewed-by: Hugo Landau <ce9fa1e55a72fc9b85dd06e47ea2c07848fb7d2c@openssl.org>
Reviewed-by: Tomas Mraz <2bc6038c3dfca09b2da23c8b6da8ba884dc2dcc2@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18132)

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl