Simplify the logic on when to perform tree conflict checking by reversion some of the logic to check unless a few specific conditions are true.
Simplify the logic on when to perform tree conflict checking by reversion
some of the logic to check unless a few specific conditions are true.

* subversion/libsvn_wc/update_editor.c
  (add_file): Remove unused variable. Just check for addition instead of
    where the node is copied/moved from as we can't rely on the path being
    related anyway. Don't check for obstructing directories in single-db
    mode. A file can never be a wc-root. Simplify if construct by just
    avoiding the cases that we want to specialize.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion