Cannot use both short and long forms for task in create-repo

The client currently does not allow 'reference' types for arguments. This type would mean a variable could be either a string (transmitted as a string) or a JSON string (transmitted as JSON). The immediate need for this feature is `create-repo`'s `task` argument to accept both forms:

razor create-repo --name name --iso-url some_url --task noop

and

razor create-repo --name name --iso-url some_url --task '{"name": "noop"}'

If the 'reference' argument can be parsed as JSON, it will use JSON, otherwise it will send the whole string.