unused reservation methods from db api

[Liyingjun]

There are several unused reservation methods are not called directly, so it could be removed from the db API.
Here are the methods:
* reservation_create https://github.com/openstack/cinder/blob/master/cinder/db/api.py#L695
* reservation_get https://github.com/openstack/cinder/blob/master/cinder/db/api.py#L702
* reservation_get_all_by_project https://github.com/openstack/cinder/blob/master/cinder/db/api.py#L707
* reservation_destroy https://github.com/openstack/cinder/blob/master/cinder/db/api.py#L712

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/58985

[Openstack Gerrit (openstack-gerrit)]

Related fix proposed to branch: master
Review: https://review.openstack.org/88077

[Openstack Gerrit (openstack-gerrit)]

Reviewed: https://review.openstack.org/58985
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=be4102b0577937c0193703ace9ae7591197341de
Submitter: Jenkins
Branch: master

commit be4102b0577937c0193703ace9ae7591197341de
Author: liyingjun <email address hidden>
Date: Fri Nov 22 12:15:49 2013 +0800

    Remove unused reservation methods from db.api

    There are several unused reservation methods are not called directly,
    so it could be removed from the db API.

    closes-bug: #1255925

    Change-Id: I8dffa1d4222da162e55ddd6cfce656b4620f3fad

[Openstack Gerrit (openstack-gerrit)]

Related fix proposed to branch: master
Review: https://review.openstack.org/90165

[Openstack Gerrit (openstack-gerrit)]

Reviewed: https://review.openstack.org/90165
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=d09f0d44707fe0aaa087b603dc6d8a29318f4a40
Submitter: Jenkins
Branch: master

commit d09f0d44707fe0aaa087b603dc6d8a29318f4a40
Author: Walter A. Boring IV <email address hidden>
Date: Thu Apr 24 10:44:37 2014 -0700

    Remove unused volume instance_uuid methods

    This patch removes a db api call that is only
    used in unit tests.

    Change-Id: Ic686eacdee21d13f8c7c7a16d7353211abc7579a
    Related-Bug: #1255925