TheanoWithCuda: cudnn shouldn't be optional or list wrapped #26263

* python27.withPackages drops nested propagatedBuildInputs
* not clear why cudnn was optional to begin with

pkgs/development/python-modules/Theano/theano-with-cuda/default.nix

@@ -56,7 +56,8 @@ buildPythonPackage rec {
     pycuda
     cudatoolkit
     libgpuarray
-  ] ++ (stdenv.lib.optional (cudnn != null) [ cudnn ]);
+    cudnn
+  ];
 
   passthru.cudaSupport = true;
 }