flake8 fix and python 3 syntax fix

theano/sandbox/cuda/__init__.py

@@ -602,7 +602,7 @@ def use(device,
                         warn = ("Your CuDNN version is more recent then Theano."
                                 " If you see problems, try updating Theano or"
                                 " downgrading CuDNN to version 4.")
-                except Exception, e:
+                except Exception:
                     pass
                 print("Using gpu device %d: %s (CNMeM is %s, CuDNN %s)" % (
                     active_device_number(),

theano/sandbox/cuda/dnn.py

@@ -7,7 +7,7 @@ from theano import Apply, tensor, config, Variable
 from theano.scalar import as_scalar, constant, Log
 from theano.gradient import DisconnectedType, grad_not_implemented
 from theano.gof import Optimizer, local_optimizer, COp
-from theano.gof.type import CDataType, Generic
+from theano.gof.type import CDataType
 from theano.compile import optdb
 from theano.compile.ops import shape_i
 from theano.tensor.nnet import LogSoftmax, SoftmaxGrad