Fix to bug #587, http://bugs.mariadb.com/show_bug.cgi?id=587

buffer.c:gwbuf_make_contiguous: hint wasn't duplicated to new GWBUF struct. As a result hints were lost if query rewriting resulted in longer query than the original.

server/core/hint.c

@@ -38,6 +38,8 @@
  *
  * @param hint		The hint list to duplicate
  * @return 	A duplicate of the list
+ * 
+ * Note : Optimize this to use version numbering instead of copying memory
  */
 HINT *
 hint_dup(HINT *hint)