MB-3224: Rate limit ns_port_server log messages to 100/sec
MB-3224: Rate limit ns_port_server log messages to 100/sec

This will help us avoid running the node out of RAM with messages in
error_logger's mailbox if we get a spammy port under heavy disk I/O
conditions.

Change-Id: I141c6e3fecec92a895c8a2972578140e1e65337c
Reviewed-on: http://review.membase.org/4143
Reviewed-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>
Tested-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>

pavel-blagodov/ns_server,mschoch/ns_server,mschoch/ns_server,ceejatec/ns_server,ceejatec/ns_server,membase/ns_server,nimishzynga/ns_server,membase/ns_server,t3rm1n4l/ns_server,daverigby/ns_server,pavel-blagodov/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,vzasade/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,daverigby/ns_server,membase/ns_server,mschoch/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,ceejatec/ns_server,vzasade/ns_server,nimishzynga/ns_server,daverigby/ns_server,mschoch/ns_server,ceejatec/ns_server,vzasade/ns_server,t3rm1n4l/ns_server,daverigby/ns_server,membase/ns_server,mschoch/ns_server,pavel-blagodov/ns_server,mschoch/ns_server,daverigby/ns_server,membase/ns_server,pavel-blagodov/ns_server,vzasade/ns_server,membase/ns_server,nimishzynga/ns_server,nimishzynga/ns_server,ceejatec/ns_server