uzbl: Fix wrong python site-package path

[HappyEnt]

Motivation for this change

Uzbl fails to build because of wrong python site-package path ('python3.5' expected vs 'python3.4' as it is now). An alternative fix would be specifying the python version to be used as 3.4.

Things done

• Tested using sandboxing
  (nix.useChroot on NixOS,
  or option build-use-chroot in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • OS X
  • Linux
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

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[mention-bot]

@HappyEnte, thanks for your PR! By analyzing the annotation information on this pull request, we identified @dgonyeo, @7c6f434c and @lethalman to be potential reviewers

[FRidh]

please use $out/python.sitePackages instead.
https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/interpreters/python/3.5/default.nix#L112

[FRidh]

in this case that would be python3.sitePackages

[joachifm]

This looks ready to me, is it? @HappyEnte please squash the commits.

[FRidh]

just having a closer look at this package, and there's more wrong with it. The expression mixes python 2 and 3. Python packages are added as buildInputs, which is wrong, since it will need pygtk during runtime.

[FRidh]

Fixed with bae6ad8