COSMIT some pep8

sklearn/cluster/tests/common.py

sklearn/cluster/tests/test_hierarchical.py

sklearn/cluster/tests/test_mean_shift.py

sklearn/cluster/tests/test_spectral.py

sklearn/covariance/tests/test_graph_lasso.py

sklearn/datasets/tests/test_20news.py

sklearn/datasets/tests/test_lfw.py

sklearn/datasets/tests/test_mldata.py

sklearn/datasets/tests/test_svmlight_format.py

sklearn/hmm.py

sklearn/metrics/tests/test_metrics.py

sklearn/mixture/gmm.py

sklearn/mixture/tests/test_dpgmm.py

sklearn/mixture/tests/test_gmm.py

sklearn/neighbors/tests/test_neighbors.py

sklearn/tree/tests/test_tree.py

sklearn/utils/tests/test_fixes.py

sklearn/utils/tests/test_graph.py

sklearn/utils/tests/test_svd.py

sklearn/utils/tests/test_weighted_mode.py