Allow configure cinder with the nfs driver

This patch allow to use nfs as cinder driver.

To use it, in the localrc we can now set

CINDER_DRIVER=nfs
CINDER_NFS_SERVERPATH=172.16.0.50:/export_cinder

The nfs-server is not setup by devstack.

Change-Id: I8e240d00b58f272d04ab2c0922c551b1f7266260
xenapi: always reset JeOS's network

If the JeOS template contained an exotic network configuration, the VM
prep step might fail. This patch resets the networking of the VM before
starting it.

Fixes bug 1245607

Change-Id: I921f1fdd0709d7a7760c4bb165e32f3898098bff
Merge "Allow configure cinder with the nfs driver"
Merge "xenapi: always reset JeOS's network"