increase handoff ack window from 100 to 1000
increase handoff ack window from 100 to 1000

planobe/riak,yangchengjian/riak,xuejianhai/riak_search,basho/riak_search,biddyweb/riak,elkingtonmcb/riak,glickbot/riak,basho/riak,GabrielNicolasAvellaneda/riak,DavidAlphaFox/riak,planobe/riak,xuejianhai/riak_search,basho/riak_search,authbox-lib/riak,wwezhuimeng/riak_search,wwezhuimeng/riak_search,laurenrother/riak,amyvmiwei/riak,xuejianhai/riak