Merge pull request #44 from andrewhsu/sup

[18.09] Fix supervisor healthcheck throttling
diff --git a/client/client.go b/client/client.go
index 7475d3f..5031502 100644
--- a/client/client.go
+++ b/client/client.go
@@ -413,7 +413,7 @@
 func (cli *Client) Dialer() func(context.Context) (net.Conn, error) {
 	return func(ctx context.Context) (net.Conn, error) {
 		if transport, ok := cli.client.Transport.(*http.Transport); ok {
-			if transport.DialContext != nil {
+			if transport.DialContext != nil && transport.TLSClientConfig == nil {
 				return transport.DialContext(ctx, cli.proto, cli.addr)
 			}
 		}