Remove one-liners for compatibility with Py2.4

tests/unittest_tools.py

@@ -279,7 +279,6 @@ class InferShapeTester:
 
 class WrongValue(Exception):
     def __init__(self, expected_val, val, rtol, atol):
-        Exception.__init__(self)  # to be compatible with python2.4
         self.val1 = expected_val
         self.val2 = val
         self.rtol = rtol

theano/gradient.py

@@ -1935,7 +1935,6 @@ class GradientError(Exception):
     def __init__(
         self, arg, err_pos, shape, val1, val2, abs_err, rel_err, abs_tol, rel_tol
     ):
-        Exception.__init__(self)  # to be compatible with python2.4
         self.arg = arg
         self.err_pos = err_pos
         self.shape = shape