Add volume driver for Huawei HVS storage system

Huawei OceanStor HVS-series enterprise storage system is an optimum
storage platform for next-generation data centers that feature
virtualization, hybrid cloud, simplified IT, and low carbon footprints.

This patch add an iSCSI driver and a FC driver for Huawei HVS storage
system, using REST. We define a common module for both iSCSI driver and
FC driver. The drivers support volume type, QoS.

Implements: blueprint huawei-hvs-volume-driver
Change-Id: Ibdfed7df6d347e00f498694898c88dfa641559eb
New update_snapshot_status API

Adds new snapshot_actions module

Update_snapshot_status: Allows updating of 'state' and
'progress' fields of a snapshot.  This is used by Nova
to inform Cinder of its outcome when performing snapshot
operations for attached volumes.  Updates are restricted
to a subset of possible start and finish states.

Implements blueprint qemu-assisted-snapshots

Change-Id: I54772f794b97e1cc6b24b121b757219248e37109
Merge "New update_snapshot_status API"
Merge "Add volume driver for Huawei HVS storage system"