MB-5904: sanitize process backtraces

Change-Id: Ia529cf8cbbdb221d1ba44519cfaa0a66393f07ed
Reviewed-on: http://review.couchbase.org/28254
Reviewed-by: Artem Stemkovski <artem@couchbase.com>
Tested-by: Artem Stemkovski <artem@couchbase.com>