Extend a swig-py test.

* subversion/bindings/swig/python/tests/client.py
  (proplist_receiver_trunk, proplist_receiver_dir1): Change scope.
  (test_inherited_props): Verify callbacks are called.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1464909 13f79535-47bb-0310-9956-ffa450edef68