pythonPackages.pyramid_chameleon: fix build by patching tests

looking into this part of the test suite it appears it started as a
modified copy of part of the main pyramid test suite. presumably this
line simply never got converted - change it to match the similar
imports.

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

@@ -16,6 +16,11 @@ buildPythonPackage rec {
     sha256 = "d176792a50eb015d7865b44bd9b24a7bd0489fa9a5cebbd17b9e05048cef9017";
   };
 
+  patches = [
+    # https://github.com/Pylons/pyramid_chameleon/pull/25
+    ./test-renderers-pyramid-import.patch
+  ];
+
   propagatedBuildInputs = [ chameleon pyramid zope_interface setuptools ];
 
   meta = with stdenv.lib; {