[MRG+1] Fix FeatureAgglomeration docs

The docs are not displayed properly here, http://scikit-learn.org/stable/modules/generated/sklearn.cluster.FeatureAgglomeration.html (I keep running into these)
Ok. Sorry for being dense, but do I do something like `del self.fit_predict` at initialization? Because doing `FeatureAgglomeration.fit_predict` simply raises a NameError. I think this can be done if the object is initialized outside, no?