Editing collection: error 500 if collection name is removed

Resolves issue: http://code.google.com/p/otwarchive/issues/detail?id=1841

Controller checks to make sure the collection has a name before it proceeds with processing the update method. If there is not a name, the user is given a meaningful error and sent back to the 'Edit' form.
Can you explain why this fixes it as It is not blindingly obvious.