afsd: CellItems doesn't apply to memcache mode

afsd: CellItems doesn't apply to memcache mode

avoid a potential panic from passing a bogus path into the kernel for
evaluation, in memcache mode.

Reviewed-on: http://gerrit.openafs.org/3651
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 6edcb1830480ef55d9dcb8a3b4735c30d802cbe4)

Change-Id: I570372cae294b8060fbd77ed58939129ad56dd5d
Reviewed-on: http://gerrit.openafs.org/3678
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>