lower the precission of the test of the gradient of ConvOp only when dx or dy !=1.

theano/sandbox/test_conv.py

@@ -550,8 +550,8 @@ class TestConvOp(unittest.TestCase):
                                     print mode, imshp, kshp, un_b, un_k, ss
                                     #TODO the tolerance needed to pass is very high for float32(0.17). Is this acceptable? Expected?
 				    tol = None
-				    if typ=="float32":
-					tol = 0.17
+                                    if typ=="float32" and (ss[0]!=1 or ss[1]!=1):
+					tol = 0.1
                                     utt.verify_grad(test_i, [imgvals],
                                                     cast_to_output_type=True,
                                                     tol=tol)