CLOUDSTACK-2587: netscaler_pod_ref DB upgrade is missing from 3.0.2 to
4.x

added missing schema as part of 4.0 to 4.1 upgrade
CLOUDSTACK-2656: UUID column for all 4.0 schema entities should be
populated when they are upgraded to 4.1
CLOUDSTACK-862 Updated documentation with the new features available in
the Nicira NVP plugin.