EA-1158: misc fixes
EA-1128: Renamed NBD fd recv vars for clarity and use a new fd/id pair
for the UNIX domain socket.
EA-1158: remove wrong assert
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier
EA-1158: use a UUID as the VBD identifier