tree cad12da8c4b67754fee9a6b922e62fca532918be
parent f7677674d2f818dae7ee99a347328f88ad4df625
author Matthew Treinish <mtreinish@kortar.org> 1419032743 -0500
committer Matthew Treinish <mtreinish@kortar.org> 1419032743 -0500

Improve error message on exception raised by get_default

This commit adds a missing message from the InvalidConfiguration
exception raised by the get_default method in the credentials classes.
Without an explanatory message it is very difficult for users to
identify the cause of the configuration error.

Change-Id: I709500fd32bdc86766de4f72e2032591c2f7aaa3