Merge pull request matplotlib#1392 from efiring/fix_hist_step

Fix by Yannick Copin for hist autoscaling bug; closes issue matplotlib#841

Author: efiring

lib/matplotlib/axes.py

@@ -8141,7 +8141,7 @@ def hist(self, x, bins=10, range=None, normed=False, weights=None,
 
             x[0::2], x[1::2] = bins, bins
 
-            minimum = min(bins)
+            minimum = np.min(n)
 
             if align == 'left' or align == 'center':
                 x -= 0.5*(bins[1]-bins[0])