move and clarify ulimit check
move and clarify ulimit check

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