The current documentation on customizing focuses on
registering/unregistering components. While this is simple and
effective at a high-level, fine-grained customizations like overriding
individual allowed() methods uses a different approach.
This confuses n00bcakes like myself, so add an explicit example of
dropping Floating IPs support to spell it out.
Fixes Bug: 1210419
Change-Id: Ib9b1579b33d48c7b2bd9bf3ad96cd303210a4420
e1ab6c3d8c