Add tests for the Python bindings of various auth prompt providers.
Add tests for the Python bindings of various auth prompt providers.

* subversion/bindings/swig/python/tests/auth.py
  (test_invalid_cred_kind, test_credentials_get_username,
  test_credentials_get_simple, test_credentials_get_ssl_client_cert,
  test_credentials_get_ssl_client_cert_pw): New functions.

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