AZ 1018: fix busy_dist_port monitoring
AZ 1018: fix busy_dist_port monitoring

Changes to the `riak_sysmon` section of app.config:

* Reduce `port_limit` from 30 -> 2
* Double `gc_ms_limit` to 100 milliseconds
* Quadruple `heap_word_limit` to about 40M
* Add `true` entries for `busy_port` and `busy_dist_port`

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