Add shelve and unshelve info into devref doc

The diagram on http://docs.openstack.org/developer/nova/devref/vmstates.html
does not currently show the "SHELVED_OFFLOADED" state and the
associated "shelve", "shelveOffload" and "unshelve" state transitions.

Change-Id: I50eb07a84336160b8120ca294598576eeb982d28
Closes-Bug: #1394215
Extend clean_shutdown to the compute rpc layer

Adds the clean_shutdown parameter added to stop, resize, rescue,
shelve and shelve_offload in Juno to the compute rpc layer.  This
will in turn allow us to extend the API to provide a
forced-shutdown option to those operations.

Change-Id: Ie24c66e5006e64ef8b45d9d5056cc7876481a2f8
Partially-Implements: blueprint user-defined-shutdown
Add support for clean_shutdown to stop in compute api layer

Change Iec3dfd17725440958aac395ebc471e51afd6522e added
clean_shutdown support to the compute manager in Juno.
This change is part of a set to extend that to the compute
API layer, which will in turn allow us to extend the REST API
to provide a forced-shutdown option to those operations.

Change-Id: I38707cf869705f983ab35e549d95dc4be4811ece
Partially-Implements: blueprint user-defined-shutdown
Add support for clean_shutdown to shelve in compute api layer

Change Iec3dfd17725440958aac395ebc471e51afd6522e added
clean_shutdown support to the compute manager in Juno.
This change is part of a set to extend that to the compute
API layer, which will in turn allow us to extend the REST API
to provide a forced-shutdown option to those operations.

Change-Id: I24dfef04cd0cddbff72267b93e0148b8fb204717
Partially-Implements: blueprint user-defined-shutdown
Add support for clean_shutdown to rescue in compute api layer

Change Iec3dfd17725440958aac395ebc471e51afd6522e added
clean_shutdown support to the compute manager in Juno.
This change is part of a set to extend that to the compute
API layer, which will in turn allow us to extend the REST API
to provide a forced-shutdown option to those operations.

Also adds a couple of missing unit test cases for rescue to the
compute_api tests

Change-Id: I5f00f63742fac89fea65149582f36866146e86f5
Partially-Implements: blueprint user-defined-shutdown
Merge "Extend clean_shutdown to the compute rpc layer"
Merge "Add support for clean_shutdown to stop in compute api layer"
Merge "Add support for clean_shutdown to shelve in compute api layer"
Merge "Add support for clean_shutdown to rescue in compute api layer"
Merge "Add shelve and unshelve info into devref doc"