implemented node quota fuzzyness for nodes being added
implemented node quota fuzzyness for nodes being added

Default value is 5 megs and MEMBASE_RAM_FUZZYNESS environment variable
overrides that value.

Change-Id: I4b0c9a1e0dcf530f367817312d829be82b4ea81b
Reviewed-on: http://review.membase.org/3748
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>

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