[MRG] DOC Refactor example to remove ambiguity in understanding param order

Fixes #3267
And it failed [this](https://github.com/scikit-learn/scikit-learn/blob/master/sklearn/feature_extraction/tests/test_text.py#L773) test alone. 

The best vectorizer's norm for `OrderedDict` based `GridSearchCV` was `l1`, but the one given in the test is `l2` ( which I presume was determined from the output of the search itself rather than manual verification? ). 

I am not sure if that should be an issue... Please let me know your views about the same...