proxychains-ng: add license information

[Peter: strip whitespace]
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/proxychains-ng/proxychains-ng.mk

@@ -7,6 +7,8 @@
 PROXYCHAINS_NG_VERSION = 4.6
 PROXYCHAINS_NG_SOURCE = proxychains-$(PROXYCHAINS_NG_VERSION).tar.bz2
 PROXYCHAINS_NG_SITE = http://downloads.sourceforge.net/project/proxychains-ng
+PROXYCHAINS_NG_LICENSE = GPLv2+
+PROXYCHAINS_NG_LICENSE_FILES = COPYING
 
 define PROXYCHAINS_NG_CONFIGURE_CMDS
 	cd $(@D) && \