netplug: add license information

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/netplug/netplug.mk

@@ -7,6 +7,8 @@
 NETPLUG_VERSION = 1.2.9.2
 NETPLUG_SOURCE = netplug-$(NETPLUG_VERSION).tar.bz2
 NETPLUG_SITE = http://www.red-bean.com/~bos/netplug
+NETPLUG_LICENSE = GPLv2
+NETPLUG_LICENSE_FILES = COPYING
 
 define NETPLUG_BUILD_CMDS
 	$(MAKE) $(TARGET_CONFIGURE_OPTS) -C $(@D)