vlserver: Avoid atoi for vol ids

vlserver: Avoid atoi for vol ids

Reviewed-on: http://gerrit.openafs.org/6050
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>
(cherry picked from commit d113c0eb8ac4717cafd7747a78c5aa3b649b8e68)

Change-Id: If965a7442262048048be9eca3e643c01d7b5c277
Reviewed-on: http://gerrit.openafs.org/6318
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Derrick Brashear <shadow@dementix.org>