Revert "Revert "build and install saslauthd-port from cbauth package""

This reverts commit f2d748c3e7b75278936fa5b5e39408578b7a42bc.

This restores Alk's original change 67d97c8ddf2d34fdafd1fae09234d9f1f55139e1
which it turns out was likely fine in the first place.

Change-Id: I71a0bfcd7a610fe7ec7812beebb6a9c892d142c3
Reviewed-on: http://review.couchbase.org/44223
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>