Don't use a baton value for something that we can just calculate later.

* subversion/libsvn_wc/wc_db.c
  (op_delete_baton_t): Remove unneeded variable.
  (delete_node): Calculate delete depth.
  (op_delete_many_txn): Update caller. Move baton out of loop.
  (svn_wc__db_op_delete): Update caller.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1448995 13f79535-47bb-0310-9956-ffa450edef68