Support host type specific block volume attachment

When Cinder attaches a Fibre-Channel volume it uses information kept in the connector. The connector contains information, such as a compute or storage nodes host port WWPNs. The Cinder driver uses this information to configure access for the compute node in the storage subsystem. This blueprint proposes to add the output of platform.machine() and sys.platform to the connector when the connector is created by Cinder. Another blueprint has been opened to have Nova add the same information when the connector is created by Nova.
Some storage subsystems, such as DS8000 support different host types. This information can be used by the Cinder driver to determine the proper host type.