Update github.com/hashicorp/go-immutable-radix

vendor/github.com/hashicorp/go-immutable-radix/.gitignore

@@ -1,24 +0,0 @@
-# Compiled Object files, Static and Dynamic libs (Shared Objects)
-*.o
-*.a
-*.so
-
-# Folders
-_obj
-_test
-
-# Architecture specific extensions/prefixes
-*.[568vq]
-[568vq].out
-
-*.cgo1.go
-*.cgo2.c
-_cgo_defun.c
-_cgo_gotypes.go
-_cgo_export.*
-
-_testmain.go
-
-*.exe
-*.test
-*.prof

vendor/github.com/hashicorp/go-immutable-radix/.travis.yml

@@ -1,3 +0,0 @@
-language: go
-go:
-  - tip

vendor/github.com/hashicorp/go-immutable-radix/iradix.go

@@ -89,7 +89,7 @@ func (t *Txn) writeNode(n *Node) *Node {
 	}
 
 	// Mark this node as modified
-	t.modified.Add(n, nil)
+	t.modified.Add(nc, nil)
 	return nc
 }