Fix volume upload failure with glance_api_version=2

Fix volume upload failure with glance_api_version=2

When the volume has additional image properties, upload-to-image
using glance API version 2 will fail with the following error.

  Failed validation u'type' in schema[u'additionalProperties']:
      {u'type': u'string'}

This is due to non core properties passed as a dict to the key
'properties'. It is valid in Image API v1, but the additional
properties must be passed just like core properties in v2.

Change-Id: Ib32c92a8be170b5f43a34e69155398dfc1a8cbcd
Closes-Bug: #1527324