Get rid of some unnecessary commented out code (issue #6849)

There is a lot of false positives (see [attached logs](http://code.google.com/p/sympy/issues/detail?id=3750#c1)), so I don't think that we should automate such cleanup.

fixes #6849
In case it's hard to believe that you have to renorm self you can see that it is necessary. In retrospect, the better place to handle this is in a test that asserts that the value changed and is correct...I'll post an example here.