python.pkgs.pytestdjango: remove duplicate expression

We already have an expression. This one wasn't referenced anywhere.

pkgs/development/python-modules/pytestdjango.nix

@@ -1,21 +0,0 @@
-{ stdenv, buildPythonPackage, fetchurl
-, pytest, django, setuptools_scm
-}:
-buildPythonPackage rec {
-  name = "pytest-django-${version}";
-  version = "3.1.2";
-
-  src = fetchurl {
-    url = "mirror://pypi/p/pytest-django/${name}.tar.gz";
-    sha256 = "02932m2sr8x22m4az8syr8g835g4ak77varrnw71n6xakmdcr303";
-  };
-
-  buildInputs = [ pytest setuptools_scm ];
-  propagatedBuildInputs = [ django ];
-
-  meta = with stdenv.lib; {
-    description = "py.test plugin for testing of Django applications";
-    homepage = http://pytest-django.readthedocs.org/en/latest/;
-    license = licenses.bsd3;
-  };
-}