stdenv.mkDerivation: remove duplicate assertions

pkgs/stdenv/generic/make-derivation.nix

@@ -374,17 +374,6 @@ let
 
       ...
     }@attrs:
-
-    # Policy on acceptable hash types in nixpkgs
-    assert
-      attrs ? outputHash
-      -> (
-        let
-          algo = attrs.outputHashAlgo or (head (splitString "-" attrs.outputHash));
-        in
-        if algo == "md5" then throw "Rejected insecure ${algo} hash '${attrs.outputHash}'" else true
-      );
-
     let
       # TODO(@oxij, @Ericson2314): This is here to keep the old semantics, remove when
       # no package has `doCheck = true`.