volser: Remove unused variable

volser: Remove unused variable

tid is now unused - remove it to avoid a warning.

Reviewed-on: http://gerrit.openafs.org/6743
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit fd19b39b151e3dddd18b4280252ac3e0fdf3964d)

Change-Id: Ib402c84689d61baefed3b76138f7fac7c2b36de0
Reviewed-on: http://gerrit.openafs.org/6771
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Alistair Ferguson <alistair.ferguson@mac.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>