Update iterator to detect when the query parent ends, and automatically exit. Fixes bug bz://564 related to processes lingering after a query dies.
Update iterator to detect when the query parent ends, and automatically exit. Fixes bug bz://564 related to processes lingering after a query dies.

xuejianhai/riak_search,wwezhuimeng/riak_search,basho/riak_search,basho/riak_search,xuejianhai/riak_search,wwezhuimeng/riak_search