Add clone volume and extend volume functions to HUS Driver

[Lakhinder Walia]

1. Add create_cloned_volume() api.
2. Add extend_volume() api.
3. Minor reorg of other code.
4. New self tests for #1 and #2 above.

(The driver shall meet the minimum requirements for Havana and Iceland releases).

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/39841

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/39841
Committed: http://github.com/openstack/cinder/commit/758a4be3b06e4b635f0ac62675ca75f43cab08f8
Submitter: Jenkins
Branch: master

commit 758a4be3b06e4b635f0ac62675ca75f43cab08f8
Author: Lakhinder Walia <email address hidden>
Date: Thu Aug 1 16:43:45 2013 -0700

    Add minimum features in HDS driver (for Havana & Icehouse)

    * Add create_cloned_volume() api.
    * Add extend_volume() api.
    * Reorganized some connection state keeping into _loc_info() function.
      Earlier this logic was spread out in various calls.
    * New self tests for #1 and #2 above.

    Change-Id: I6a88164ee0a427519c7fab6f6a852d46ec46176c
    Fixes: bug #1207560