Comment 1 for bug 1712041

For this bug I found two problems:
1. Heat updates the volume_reality with property 'read_only' from the live data when parse_live_resource_data(), but in
fact cinder returns the key 'readonly' in volume details info, not the key 'read_only'
2. because the reason above, heat will call update_all_metadata() when handle_update(), there is a bug in cinder, all metadata api can be used since the microversion 3.15, and I found a bug of cinder: https://bugs.launchpad.net/cinder/+bug/1712192

So, we fix the first problem in heat.