Sure, done and pushed.

Actually, I meant to go back and review this code, but I forgot; if I move the btree handle release to after the call to `__wt_conn_btree_apply` things go pear-shaped pretty fast, and I meant to figure that out.   Any idea why it's not possible to retrieve a handle, call `__wt_conn_btree_apply` and then release the handle?   You have to save/restore WT_SESSION.dhandle, but I'm not sure why that's not sufficient.

__wt_conn_btree_apply() should probably save/restore WT_SESSION.dhandle, come to think of it.