pythonPackages.request-cache: Move to own file

pkgs/development/python-modules/requests-cache/default.nix

@@ -0,0 +1,21 @@
+{ stdenv, buildPythonPackage, fetchPypi
+, mock, requests, six, urllib3 }:
+
+buildPythonPackage rec {
+  pname = "requests-cache";
+  version = "0.4.13";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "18jpyivnq5pjbkymk3i473rihpj2bgikafpha7xvr6w736hiqmpy";
+  };
+
+  buildInputs = [ mock ];
+  propagatedBuildInputs = [ requests six urllib3 ];
+
+  meta = with stdenv.lib; {
+    description = "Persistent cache for requests library";
+    homepage = https://pypi.python.org/pypi/requests-cache;
+    license = licenses.bsd3;
+  };
+}