Describe the bug
When encountering an access error trying to publish the OMEMO device list, converse.js attempts to reconfigure the node's access by fetching and updating the node configuration. Fetching of the node configuration fails with a bad request error due to using the incorrect namespace.

According to the samples in XEP-60, the namespace for fetching the node configuration should be http://jabber.org/protocol/pubsub#owner, converse.js currently uses http://jabber.org/protocol/pubsub.