Update admin.py (#22646)

src/olympia/amo/admin.py

@@ -183,7 +183,7 @@ class AMOModelAdmin(admin.ModelAdmin):
         js = (
             'js/admin/ip_address_search.js',
             'js/exports.js',
-            'js/node_lib/netmask.js',
+            'netmask/lib/netmask.js',
         )
         css = {'all': ('css/admin/amoadmin.css',)}