Add support for nbd1 device for dump

For Dump offload use-case, we are using nbd1 device
this commit is to add support for nbd1 device in state_hook

(From meta-phosphor rev: 0d878479caa21c76606e041e18830d03c2d6fec2)

Signed-off-by: Ravi Teja <raviteja28031990@gmail.com>
Change-Id: I6710f97d1ba67e801fbfa7eae9c13aaf9b4963c8
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>