Remove unused DB API get_pods_by_bay_uuid and Pod object API list_by_bay_uuid

[Vilobh Meshram]

In following db api,

get_pods_by_bay_uuid

The exception returned when bay is not found is wrong.

The approach should be
1. Check for valid Bay if not throw an exception
2. If valid Bay is found get the list of pods for this particular bay-uuid

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/217908

[Vilobh Meshram (vilobhmm)]

After further analysis found that get_pods_by_bay_uuid is not used by any consumer. Along with it no consumers lists POD by using list_by_bay_uuid https://github.com/openstack/magnum/blob/master/magnum/objects/pod.py#L101

Proposed that we should clean up the dead code. Discussed this with Kennan and hongbin on IRC and hence proposing the fix to clean up dead code. If all the cores agree we can merge this.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/217908
Committed: https://git.openstack.org/cgit/openstack/magnum/commit/?id=2d74d223e5457e2d3a93556128f742890a882ad6
Submitter: Jenkins
Branch: master

commit 2d74d223e5457e2d3a93556128f742890a882ad6
Author: Vilobh Meshram <email address hidden>
Date: Thu Sep 24 17:37:10 2015 -0700

    Remove unused DB API and Pod object API

    This patch removes unused DB API 'get_pods_by_bay_uuid',
    Pod object layer API 'list_by_bay_uuid' and the
    associated unit tests. There are no consumers of this
    code as this code is not invoked by anyone. Cleaning
    this up will help to remove some dead code.

    Change-Id: If0bed177d190040720e50bf15dfefb5de5a7b999
    Closes-Bug: #1489572