The REST Client queries the /info endpoint to check whether the API URL
is scoped to a tenant or not. If it is, do not use the "tenant" argument
in method calls.
Make the --tenant argument optional in the CLI. The user gets an error
if the provided API URL is not scoped and the --tenant argument is
missing; or if the API URL is scoped to a specific tenant, and --tenant
is set to a different tenant.
Change-Id: I338c9a690c0ae433956e070010e68d4a6a90e183
314860f10b