Revert "openvpn: require a fully setup network instead of just the interface."

This reverts commit 0652b7f43cdf71dd5fc894d0c9d65d3de9bfdb4c.
haskell-STMonadTrans: new expression

Conflicts:
	pkgs/top-level/haskell-packages.nix
haskell-equivalence: new expression
haskell-boxes: new expression

Conflicts:
	pkgs/top-level/haskell-packages.nix
Agda: add 2.4.0.1, 2.3.2.2 is still the default for now

Conflicts:
	pkgs/development/compilers/agda/2.3.2.2.nix
	pkgs/development/compilers/agda/agda.nix
	pkgs/development/compilers/agda/stdlib-0.7.nix
	pkgs/development/libraries/haskell/Agda/default.nix
	pkgs/top-level/haskell-packages.nix
Merge branch 'backports!'

Conflicts:
	pkgs/development/compilers/agda/2.3.2.2.nix
	pkgs/top-level/haskell-packages.nix
cleanup agda diffs
agda-stdlib: upgrade to 0.8 (they keep changing the version scheme)
linux-3.15: upgrade to 3.15.1