fix idna error with IP addresses

spotted in #554: don't try to encode to IDNA an IP address.

Author: benoitc

src/hackney_connect.erl

@@ -39,7 +39,13 @@ connect(Transport, Host, Port, Options, Dynamic) ->
 
   Host2 = case Transport of
             hackney_local_tcp -> Host;
-            _ ->  idna:utf8_to_ascii(Host)
+            _ ->
+              case inet:parse_address(Host) of
+                {ok, _} ->
+                  Host;
+                _ ->
+                  idna:utf8_to_ascii(Host)
+              end
           end,
 
   case create_connection(Transport, Host2, Port, Options, Dynamic) of