On the 'move-tracking-2' branch: tweak the shim code.

* subversion/libsvn_delta/compat3.c
  (insert_change): Remove the (limited) handling of 'delete' operation from here.
  (delete_subtree): New function, doing a more thorough job of preparing to
    delete any subtree, which will be needed for handling more general
    sequences of operations including moves.
  (editor3_mv, editor3_rm): Update callers to use delete_subtree() instead.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/move-tracking-2@1623942 13f79535-47bb-0310-9956-ffa450edef68