http: don't reset replay count after connection

A "connection" to a server is transient, and we may reconnect to a
server in the midst of authentication failures (if the remote indicates
that we should, via `Connection: close`) or in a redirect.

src/transports/http.c

@@ -1044,7 +1044,6 @@ static int http_connect(http_subtransport *t)
 	t->proxy.stream = proxy_stream;
 	t->server.stream = stream;
 	t->connected = 1;
-	t->replay_count = 0;
 	return 0;
 
 on_error: