startdde: Cleanup

* debian/startdde/compat: Use 9.

* debian/startdde/control:
  (Build-Depends)(libgail-3-dev, libgstreamer-plugins-base0.10-dev): Remove.
  (Depends)(dde-daemon): Remove version restriction.

* debian/startdde/copyright (Source): Add url.
  (Copyright): Honor XiaBin.
  (Copyright)(debian): Add myself.