The default_project is checked at the beginning of the module.
This raises an exception if the project passed does not exist.
This logic only makes sense on resource creation, if a user
puts state=absent the module fails, even though the default
project is not relevant
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.
