Don't change the error type when adding extra error info.

theano/tensor/elemwise.py

@@ -817,8 +817,7 @@ class Elemwise(Op):
                             min_informative_str(output) + '\n'
                 errormsg += 'original exception was: ' + '\n'.join(
                         traceback.format_exception_only(*sys.exc_info()[0:2]))
-                raise Exception(errormsg)
-            else:
+
             e.args = e.args + (errormsg, )
             raise