MB-100 convert time in active task to human readable

Change-Id: Ib94f9c32e3cd74686075f26de90d565c45eb79e1
Reviewed-on: http://review.couchbase.org/24985
Tested-by: Thuan Nguyen <soccon@gmail.com>
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>