The exception message, when shade fails, will contain much more
specific information about the failure if the exception is treated
as a string. The 'message' attribute alone is usually not helpful.
Uses the latest version of shade for cleaner code. Also, always
return the key dict whether we create the key, or it already exists.
The example using public_key_file is corrected to use a full path
since ~ is not converted for us.
Toshio Kuratomi
David Shrewsbury
Lars Kellogg-Stedman
Toshio Kuratomi
Monty Taylor
Davide Guerri