illumos gate

In namespace_reload, libzfs empties the libzfs_ns_avl tree with uu_avl_teardown (really a avl_destroy_nodes in disguise) and then proceeds to insert new items without destroying and recreating the tree.

Recall what avl.h has to say about avl_destroy_nodes:

 * 3. Use avl_destroy_nodes() to quickly process/free up any remaining nodes.
 *    Note that once you use avl_destroy_nodes(), you can no longer
 *    use any routine except avl_destroy_nodes() and avl_destoy().