Symantec NFS cinder driver

Changes to support Symantec Storage Foundation Clustered File
System High Availability via NFS Cinder driver.

cert results at:
https://bugs.launchpad.net/cinder/+bug/1402147

implements: blueprint symantec-nfs-cinder-driver
Change-Id: Ie4b4785b7c93246147c8d9e6a172621f454301ae
Merge "Symantec NFS cinder driver"