Fix _post_where_to routine

The routine used 'next' instead of 'return'. Now it can return undef if
the file doesn't match the 'from' specification.
Fix error message
Make UpdateConfFile create non-existing directories

If the 'to' specification contains directories they are created if they
don't exist.
v1.24

        [Fixes]

        - CheckMimeTypes: disregard symbolic links because they don't need to
          have the svn:mime-type property set.

        - UpdateConfFile: create non-existing directories if the 'to'
          specification contains directories they are created if they don't
          exist.