Delete the chat entry identified by the name query parameter. Invoking fetch("chat-delete/"+msgid) from javascript in the client will delete a chat entry from the CHAT table.

This routine both deletes the identified chat entry and also inserts a new entry with the current timestamp and with:

• xmsg = NULL

• file = NULL

• mdel = The msgid of the row that was deleted

This new entry will then be propagated to all listeners so that they will know to delete their copies of the message too.