google-chrome: Fix fetching upstream binary

Commit aa097946d2 only fixed evaluation.

Ssince 37dbd62 however, the fetchurl call is already implied so just
changing the path will still result in fetchurl (fetchurl ...), so let's
drop the outer fetchurl.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Cc: @msteen, @benley
(cherry picked from commit 4d305102e0)

pkgs/applications/networking/browsers/google-chrome/default.nix

@@ -59,7 +59,7 @@ in stdenv.mkDerivation rec {
 
   name = "google-chrome-${version}";
 
-  src = fetchurl binary;
+  src = binary;
 
   buildInputs = [ env patchelf ];