MB-11064: bumped memcached's connections limit

11210 and it's sibling ssl ports now have limit of 30000 connections
and port 11209 now has limit of 5k.

Change-Id: I2bfa70439a6260445ec42af5778c48b00aee22bb
Reviewed-on: http://review.couchbase.org/39888
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>