Comment 1 for bug 1145490

Reviewed: https://review.openstack.org/23485
Committed: http://github.com/openstack/nova/commit/67eb495e37f3622d68bd07997b8680049a2426d1
Submitter: Jenkins
Branch: stable/folsom

commit 67eb495e37f3622d68bd07997b8680049a2426d1
Author: MotoKen <email address hidden>
Date: Mon Nov 5 19:45:11 2012 +0800

    Decouple EC2 API from using instance id

    Continuation of 0dc32690fe158e4cb11c2c9bcc65acaf73b94a7a

    Some code in ec2 api use Instance.id rather than InstanceIdMapping.id
    directly while converting ec2 id to an instance object. This is very
    dangerous if Instance.id is not equal to InstanceIdMapping.id for the
    same instance uuid.

    To avoid the id mapping confusion, this patch:

     * uses instance_id_mappings.id instead of instances.id
     * uses instance_uuid in ec2utils.id_to_ec2_inst_id
     * removes ec2utils.ec2_instance_id_to_uuid

    Fixes bug 1145490

    Change-Id: I22638f667c18eefe542b03e31f1a3aa2ce782db7
    (cherry picked from commit 79cc2a21b645138f70c6ca4b54053f69c0dde81d)