Hyper-V: add support for attaching volumes via SMB

Currently, the Hyper-V driver only allows attaching volumes via iSCSI.
The purpose of this blueprint is adding support for attaching volumes
hosted on a SMB share.

bp hyper-v-smbfs-volume-support
Change-Id: If1d6a1b724e1dee705e964cdb86cd2a69d73d7df
Merge "Hyper-V: add support for attaching volumes via SMB"