cryptominisat: Convert to new overlays system

pkgs/all-packages.nix

@@ -1,3 +1,4 @@
 self: pkgs: with pkgs; {
 
+  cryptominisat = callPackage ./cryptominisat.nix { };
 }

pkgs/cryptominisat.nix

@@ -1,11 +1,11 @@
-with import <nixpkgs> {};
+{ stdenv, fetchurl, cmake, zlib, sqlite, boost, python27, vim }:
 
 stdenv.mkDerivation {
   name = "cryptominisat-4.5.3";
 
   src = fetchurl {
     url = https://github.com/msoos/cryptominisat/archive/4.5.3.tar.gz;
-    sha256 = "0k7blcphchn7pbandbar45zp2i3xrgcayiysv9lc6kbk4l7a4k8i"; 
+    sha256 = "0k7blcphchn7pbandbar45zp2i3xrgcayiysv9lc6kbk4l7a4k8i";
   };
 
   buildInputs = [