DOC: Correct scikit-learn name in comments (#8681)

build_tools/travis/test_script.sh

sklearn/datasets/california_housing.py

sklearn/datasets/covtype.py

sklearn/datasets/kddcup99.py

sklearn/datasets/lfw.py

sklearn/datasets/mldata.py

sklearn/datasets/olivetti_faces.py

sklearn/datasets/rcv1.py

sklearn/datasets/species_distributions.py