Update SWIG Python bindings regarding recent changes to
svn_config_walk_auth_data() and friends.

* subversion/bindings/swig/core.i
  Rework svn_auth_cleanup_walk typemapping into the new
  svn_config_walk_auth_data stuffs.

* subversion/bindings/swig/python/libsvn_swig_py/swigutil_py.h
* subversion/bindings/swig/python/libsvn_swig_py/swigutil_py.c
  (svn_swig_py_config_auth_walk_func): Was svn_swig_py_auth_cleanup_func.
    Track changes made in r1466183 in the rename/reworking of the
    related C API.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1466497 13f79535-47bb-0310-9956-ffa450edef68