fix metric_id in avg_server_process_cpu
fix metric_id in avg_server_process_cpu

Change-Id: Ibe8cadf2a0014223de11132cad08e65b8fd713ca
Reviewed-on: http://review.couchbase.org/c/perfrunner/+/154890
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Korrigan Clark <11cf3ebdc6cba78053c91b2fd94cb21b47d0d02e@couchbase.com>

couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner