A cloud/domain admin should be able to create a network on any project
it is granted to.
This changes adds the possibility to pass either a project ID or
project name.
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.
The `os_network` module was incorrectly returning changed=False whether
or not the network was created. This commit makes the changed return
value useful.
With shade > 0.13.0, networks can be created that are externally
accessible. This adds a parameter for that.
Also, add RETURN documentation and 'if __name__' check around call
to main().
John R Barker
Ricardo Carrillo Cruz
Rene Moser
David Shrewsbury
Lars Kellogg-Stedman
Monty Taylor
Greg DeKoenigsberg