udp: remove ancient check

PR-URL: https://github.com/nodejs/node/pull/8088
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: bnoordhuis - Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Minwoo Jung <jmwsoft@gmail.com>

lib/dgram.js

@@ -53,9 +53,6 @@ function newHandle(type) {
     return handle;
   }
 
-  if (type == 'unix_dgram')
-    throw new Error('"unix_dgram" type sockets are not supported any more');
-
   throw new Error('Bad socket type specified. Valid types are: udp4, udp6');
 }