title: How to use cross_val_score with random_state
body: <p>I get different values for different runs. What am I doing wrong here?</p>
  <pre><code>import numpy as np
  from sklearn.ensemble import RandomForestClassifier
  from sklearn.model_selection import StratifiedKFold, cross_val_score
  
  X = np.random.random((100,5))
  y = np.random.randint(0,2,(100,))
  cross_val_score = RandomForestClassifier()
  cv = StratifiedKFold(y, random_state=1)
  s = cross_val_score(cross_val_score, X, y,scoring='roc_auc', cv=cv)
  print(s)
  # [ 0.42321429  0.44360902  0.34398496]
  
  s = cross_val_score(cross_val_score, X, y, scoring='roc_auc', cv=cv)
  print(s)
  # [ 0.42678571  0.46804511  0.36090226]
  </code></pre>