pythonPackages: remove name attribute`

The `buildPython*` function computes name from `pname` and `version`.
This change removes `name` attribute from all expressions in
`pkgs/development/python-modules`.

While at it, some other minor changes were made as well, such as
replacing `fetchurl` calls with `fetchPypi`.

pkgs/development/python-modules/python-stdnum/default.nix

@@ -1,13 +1,12 @@
-{ lib, fetchurl, buildPythonPackage, isPy3k }:
+{ lib, fetchPypi, buildPythonPackage, isPy3k }:
 
 buildPythonPackage rec {
   version = "1.9";
   pname = "python-stdnum";
-  name = "${pname}-${version}";
   # Failing tests and dependency issue on Py3k
   disabled = isPy3k;
-  src = fetchurl {
-    url = "mirror://pypi/p/python-stdnum/${name}.tar.gz";
+  src = fetchPypi {
+    inherit pname version;
     sha256 = "d587a520182f9d8aef7659cca429f4382881589c8883a0a55322b2f94970bdb3";
   };
   meta = {