After closing a changeset, new changeset will also have tags by noteSolver

[daganzdaanda]

To reproduce:

• Close a note, remember in noteSolver, upload to server
• noteSolver will add noteSolver_plugin/0.5.0; to the changeset's created_by tag and add the closed:note=note-id tag (which is cool!)
• Don't quit JOSM, make another change but don't touch any notes.
• JOSM will warn you about a closed:note tag with an empty value. Also, the created_by will still have noteSolver in it.

It's not really important, but still a small bug.