[VOL-4292] OpenOLT Adapter changes for gRPC migration

Change-Id: I5af2125f2c2f53ffc78c474a94314bba408f8bae
diff --git a/vendor/golang.org/x/net/http2/hpack/huffman.go b/vendor/golang.org/x/net/http2/hpack/huffman.go
index b412a96..a1ab2f0 100644
--- a/vendor/golang.org/x/net/http2/hpack/huffman.go
+++ b/vendor/golang.org/x/net/http2/hpack/huffman.go
@@ -105,7 +105,14 @@
 	return nil
 }
 
+// incomparable is a zero-width, non-comparable type. Adding it to a struct
+// makes that struct also non-comparable, and generally doesn't add
+// any size (as long as it's first).
+type incomparable [0]func()
+
 type node struct {
+	_ incomparable
+
 	// children is non-nil for internal nodes
 	children *[256]*node