Add num_rows_scanned_aggr and scan_cache_hit_aggr
Add num_rows_scanned_aggr and scan_cache_hit_aggr

Change-Id: I46dd87bb3ed8e494987359daad1d285c2190682b
Reviewed-on: http://review.couchbase.org/90776
Reviewed-by: Pavel Paulau <dd88eded64e90046a680e3a6c0828ceb8fe8a0e7@gmail.com>
Tested-by: Pavel Paulau <dd88eded64e90046a680e3a6c0828ceb8fe8a0e7@gmail.com>

couchbase/cbmonitor,couchbase/cbmonitor