block: drbd: drbd_receiver: Remove redundant assignment to err

Variable err is set to '-EIO' but this value is never read as
it is overwritten or not used later on, hence it is a redundant
assignment and can be removed.

Clean up the following clang-analyzer warning:

drivers/block/drbd/drbd_receiver.c:3955:5: warning: Value stored to
'err' is never read [clang-analyzer-deadcode.DeadStores].

Reported-by: Abaci Robot <[e-mail]>
Signed-off-by: Jiapeng Chong <[e-mail]>
Acked-by: Christoph Böhmwalder <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

drivers/block/drbd/drbd_receiver.c

···
 				drbd_err(device, "verify-alg of wrong size, "
 					"peer wants %u, accepting only up to %u byte\n",
 					data_size, SHARED_SECRET_MAX);
-				err = -EIO;
 				goto reconnect;
 			}