primusLib: move to fetchFromGitHub (and fix strange checksum error)

pkgs/tools/X11/primus/lib.nix

···
-{ stdenv, fetchgit
+{ stdenv, fetchFromGitHub
 , xlibsWrapper, mesa
 , nvidia_x11 ? null
 , libX11
···
 stdenv.mkDerivation {
   name = "primus-lib-20151204";
 
-  src = fetchgit {
-    url = git://github.com/amonakov/primus.git;
+  src = fetchFromGitHub {
+    owner = "amonakov";
+    repo = "primus";
     rev = "d1afbf6fce2778c0751eddf19db9882e04f18bfd";
-    sha256 = "8f095b5e2030cdb155a42a49873832843c1e4dc3087a6fb94d198de982609923";
+    sha256 = "118jm57ccawskb8vjq3a9dpa2gh72nxzvx2zk7zknpy0arrdznj1";
   };
 
   buildInputs = [ libX11 mesa ];