afsmonitor: Add missing items to fsOpNames array

The Lookup and Residency fs stats counters were missing from the
fsOpNames array. Add them in - Lookup has been missing since the
IBM release, Residency was missed when the MR-AFS code was merged.

This is still rather fragile, as there's no guarantee that
AFS_STATS_NUM_FS_RPC_OPS matches the number of elements in this
array. However, this is now correct until someone breaks it again...

Caught by coverity (#985569)

Change-Id: I22496050d5e786276a6646aa763d036449a3660d
Reviewed-on: http://gerrit.openafs.org/9314
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>