#1327 Pubsub does not report exact reason for not accepting configuration form
What steps will reproduce the problem?
Attempt to configure a pubsub node in some way that's not acceptable. E.g. an unsupported access model or a max_items exceeding pubsub_max_items.
What is the expected output?
An explanation for what part of the node config form was wrong.
What do you see instead?
What version of the product are you using?
Please provide any additional information below.
This is currently problematic because:
The check_node_config() callback is expected to return only a boolean.
Almost all pubsub methods return (boolean, error-condition).
The full error is looked up in a fixed table.