MB-100: reduce xdcr lag batch to 10 docs

also always send mutli_lag results

Change-Id: I1dff35e6a67dea46e89013f3f602bef25c3b6650
Reviewed-on: http://review.couchbase.org/24774
Reviewed-by: Pavel Paulau <pavel.paulau@gmail.com>
Tested-by: Pavel Paulau <pavel.paulau@gmail.com>