Fix a typo of netmask in config.ini.

Author: jfb8856606

config.ini

@@ -76,7 +76,7 @@ savelen= 16777216
 # Correspond to dpdk.port_list's index: port0, port1...
 [port0]
 addr=192.168.1.2
-netmask=255.255.225.0
+netmask=255.255.255.0
 broadcast=192.168.1.255
 gateway=192.168.1.1
 # IPv6 net addr