ht.h comment tweaks, upstreamed from libevent

src/common/ht.h

@@ -431,9 +431,8 @@ ht_string_hash(const char *s)
 /*
  * Copyright 2005, Nick Mathewson.  Implementation logic is adapted from code
  * by Christopher Clark, retrofit to allow drop-in memory management, and to
- * use the same interface as Niels Provos's HT_H.  I'm not sure whether this
- * is a derived work any more, but whether it is or not, the license below
- * applies.
+ * use the same interface as Niels Provos's tree.h.  This is probably still
+ * a derived work, so the original license below still applies.
  *
  * Copyright (c) 2002, Christopher Clark
  * All rights reserved.