Fix call to loop_acceptor (elixir-lang#852)

Author: gusaaaaa

getting-started/mix-otp/task-and-gen-tcp.markdown

@@ -43,6 +43,7 @@ end
 defp loop_acceptor(socket) do
   {:ok, client} = :gen_tcp.accept(socket)
   serve(client)
+  loop_acceptor(socket)
 end
 
 defp serve(socket) do
@@ -51,7 +52,6 @@ defp serve(socket) do
   |> write_line(socket)
 
   serve(socket)
-  loop_acceptor(socket)
 end
 
 defp read_line(socket) do