BUG-985 - finisher queue is unbound

BUG-985 - finisher queue is unbound

and causes out of memory error under stress

- replaced queue.offer with queue.put (blocking behavior)

Changed the initialization of the TicketFinisher queue to limit the size of the queue to 1,000 elements. Backpressure will be exerted when the max queue size has been reached. This is to fix an out-of-memory condition that occurs under heavy load when the TicketFinisher queue grows w/o bounds.

Change-Id: I619d1c27db98fec95380bef2504add3025195abc
Signed-off-by: Jan Medved <jmedved@cisco.com>
Signed-off-by: Michal Rehak <mirehak@cisco.com>