src: fix documentation url in help message

Refer to https://iojs.org/ for documentation

PR-URL: https://github.com/iojs/io.js/pull/378
Reviewed-By: Rod Vagg <rod@vagg.org>

src/node.cc

@@ -2911,7 +2911,7 @@ static void PrintHelp() {
 #endif
 #endif
          "\n"
-         "Documentation can be found at http://nodejs.org/\n");
+         "Documentation can be found at https://iojs.org/\n");
 }