MB-5904 remove passwords from cbcollect_info results

- except backtraces in diag.log

Change-Id: I9c556062cc0db2d0ef935676a6bbc2db654f6a8a
Reviewed-on: http://review.couchbase.org/28233
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>