Turn block_device_mapping.volume_size to int

Integer instead of string will allow better constrain implementation
plus Nova expects such parameter to be an integer.

This change is backward compatible, as it still accepts string values.

Change-Id: I599ea2bf77a187cc53f864a9e1a42755142211ff
Closes-Bug: #1267889
heat_keystoneclient migrate auth_token/service_catalog to v3 API

These work the same regardless of the client version

Change-Id: I2ee4a90f4ca5c58226abd2a9660c1a7bdabb1a08
blueprint: keystone-v3-only
Merge "heat_keystoneclient migrate auth_token/service_catalog to v3 API"
Merge "Turn block_device_mapping.volume_size to int"