XenAPINFS: Create volume from image (generic)

Fixes bug 1130706

Related to blueprint xenapinfs-glance-integration

This patch enables users to use any images recognised by qemu-img to
create volumes on XenAPINFS.

Change-Id: I9dd8ec237309da82ec7f73db1acb48e5b7411c9e
Implement metadata options for snapshots

This patch implements metadata for snapshots as well as
the ability to update/delete that metadata.

Implements blueprint: update-snap-metadata

Change-Id: Iec2b7a51cdc3dffad41f24807067cc6c8e7d5135
Merge "XenAPINFS: Create volume from image (generic)"
Merge "Implement metadata options for snapshots"