useful trace that logs dalayed crash callstack immediately

Change-Id: I87685f9ca020f6d64f171af86ea537c42a7f633b
Reviewed-on: http://review.couchbase.org/43620
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>