Adding a patch to NagiosGraph map file. So, Nagiosgraph will parse netint perfdata when this plugin is using cache in perfdata

check_netint has the excelent capability of cache informations in perfdata. However, NagiosGraph, by default, will create one new rrd everytime it parses the perfdata. It's painful!
This pull request adds a new map entry in NagiosGraph map file. So, NagiosGraph not create RRDs like cache_descr_*, *_in(out)_octet or ptime.