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/webencodings/default.nix

@@ -1,20 +1,19 @@
 { buildPythonPackage
 , lib
-, fetchurl
+, fetchPypi
 , pytest
 }:
 
 buildPythonPackage rec {
   pname = "webencodings";
   version = "0.5.1";
-  name = "${pname}-${version}";
 
-  src = fetchurl {
-    url = "mirror://pypi/${builtins.substring 0 1 pname}/${pname}/${name}.tar.gz";
+  src = fetchPypi {
+    inherit pname version;
     sha256 = "b36a1c245f2d304965eb4e0a82848379241dc04b865afcc4aab16748587e1923";
   };
 
-  buildInputs = [ pytest ];
+  checkInputs = [ pytest ];
 
   checkPhase = ''
     py.test webencodings/tests.py