keymap-dump: Print NoAction actions too

keymap-dump: Print NoAction actions too

The failure mode here is a little irritating:
    - server loads map with ISO_Lock action
    - server dumps keymap to string, including:
      interpret ISO_Lock+AnyOfOrAll(None) {
          action= NoAction();
      };
      as we don't (yet) print ISO_Lock actions
    - client parses keymap from string
    - client dumps keymap to string, including:
      interpret ISO_Lock+AnyOfOrAll(None) {
      };
    - this results in a syntax error

Signed-off-by: Daniel Stone <daniel@fooishbar.org>