Remove explicit dependency on amqplib

kombu already depends on amqp or amqplib depending on its
version, and no explicit access to amqplib exists in ironic code.

Update logging config to list both amqp and amqplib, as kombu
will setup one or the other.

Change-Id: I66b81e5ef13d009d01b7656fe5e61a7cffd7dcac
Merge "Remove explicit dependency on amqplib"