MB-11607 use ets table in UPR notifier to store partitions

... because it's faster

Change-Id: I9bc5586650f335e02a059ef86d963bb050114111
Reviewed-on: http://review.couchbase.org/39043
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>