kde5.applications: 16.04.2 -> 16.04.3

- Update from Applications 16.04.2 to 16.04.3.
- Remove the version number from the directory storing the Applications
  Nix expressions. It is not necessary to version the Nix expressions
  now that we keep only one version in Nixpkgs.
- Fix a bug in generate-kde-applications.sh which prevented it from
  finding its helper script.
- Automatically redirect the output of generate-kde-applications.sh to
  make the update script even easier to use.