LINUX: old kernel warning fixes

LINUX: old kernel warning fixes

 - osi_vfsop.c: struct super_block, not superblock

 - osi_vnodeops.c: initialize bypasscache

Reviewed-on: http://gerrit.openafs.org/2973
Reviewed-by: Marc Dionne <marc.c.dionne@gmail.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit ba96ebba7197420b1511bd1aae9db495398e038a)
Change-Id: I3c98809bf8763c03a6f1c27e7ebe68ddb8ad1318
Reviewed-on: http://gerrit.openafs.org/3104