fix iteration over report metrics
fix iteration over report metrics

Change-Id: I51f38a58a48cbe885c41acb08aca68d68979458d
Reviewed-on: http://review.couchbase.org/28432
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Pavel Paulau <dd88eded64e90046a680e3a6c0828ceb8fe8a0e7@gmail.com>

couchbase/cbmonitor,couchbase/cbmonitor