muninlite: Fix PKG_LICENSE information

muninlite is GPL-2.0+, not GPL-2.0 exclusively

Signed-off-by: Jonathan McCrohan <jmccrohan@gmail.com>

admin/muninlite/Makefile

@@ -14,7 +14,7 @@ PKG_RELEASE:=5
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=@SF/$(PKG_NAME)
 PKG_MD5SUM:=a8cc86f0cc536a6c22dc298f4ed55339
-PKG_LICENSE:=GPL-2.0
+PKG_LICENSE:=GPL-2.0+
 PKG_LICENSE_FILES:=LICENSE
 
 include $(INCLUDE_DIR)/package.mk