NatHelper bad private ip range

[oguilbaud]

In src/module-nat-helper.cc

The method :

       bool isPrivateAddress(const char *host) {
		return strstr(host, "10.") == host || strstr(host, "192.168.") == host || strstr(host, "176.12.") == host;
	}

use a bad private ip range address to define if private or not.
the RFC1918 #3 define this range

Class	Private Address Range
A	10.0.0.0 to 10.255.255.255
B	172.16.0.0 to 172.31.255.255
C	192.168.0.0 to 192.168.255.255