Unix CM: Update AFS_STATS_NUM_FS_RPC_OPS

There are actually 30 elements in the AFS_STATS_FS array. When the
ResidencyRpcs counter was added, the total number of operations
wasn't updated.

Fix this so that it is correct, although this still remains rather
fragile.

Reviewed-on: http://gerrit.openafs.org/9313
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit 2c8e4f839fc253abb8051bbf89d36e94a2200590)

Change-Id: Id6094e6e5007984cb080281f6a085eba958d6367
Reviewed-on: http://gerrit.openafs.org/9540
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>