Adds method to update server.pem to Amphora REST spec
Adds method to update server.pem to Amphora REST spec

In case the certificate for communicating between controller
and amphora expires we need to fail over to a new amphora
right now. This will add a way to change it in place.

Change-Id: I411eafa462976fb4878797fb4812351229feb81e

openstack/octavia,openstack/octavia,openstack/octavia