xstat: length check cm call info

Define the cm xstat function call counters with an xmacro to avoid
duplicating the list of cm function names.  This obviates the need
to update xstat_cm_test.c when new function names are added to the
cm xstat collection id 0.

Check the number of returned records when printing the function call
counts to avoid over-running when a newer xstat_cm_test client
receives data from an older cm.

Change-Id: I3c5470afb7b04167173b41bb576a4a6ec14753f7
Reviewed-on: http://gerrit.openafs.org/8741
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>