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/pytest-expect/default.nix

@@ -1,6 +1,6 @@
 { buildPythonPackage
 , lib
-, fetchurl
+, fetchPypi
 , pytest
 , u-msgpack-python
 , six
@@ -9,10 +9,9 @@
 buildPythonPackage rec {
   pname = "pytest-expect";
   version = "1.1.0";
-  name = "${pname}-${version}";
 
-  src = fetchurl {
-    url = "mirror://pypi/${builtins.substring 0 1 pname}/${pname}/${name}.tar.gz";
+  src = fetchPypi {
+    inherit pname version;
     sha256 = "36b4462704450798197d090809a05f4e13649d9cba9acdc557ce9517da1fd847";
   };