[PATCH] nbd: remove duplicate assignment

      <stuartm@connecttech.com>

Sent by Paul Clements <paul.clements@steeleye.com>, who needs to read
Documentation/SubmittingPatches..

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>