bosserver: Remove dead assignment

In the Restart RPC handler, don't assign a value to code
immediately before we use it to hold the return value of
bozo_WaitStatus.

Caught by clang-analyzer

Change-Id: I0781c57c87088cb3ba6170ca1e5c8d5053cf9001
Reviewed-on: http://gerrit.openafs.org/9231
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>