MB-11607 suppress some upr logging in UPR notifier

... because it slows down xdcr

Change-Id: I1bbb9132d685a8851c74cb45520cece70879c2d2
Reviewed-on: http://review.couchbase.org/39044
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>