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