Remove explicit dependency on amqplib

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

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

Change-Id: I716050593cde15f2a614175d9849340e5858fc32
Merge "Remove explicit dependency on amqplib"