TST: skip test_kds_colors if too old scipy installed

Author: jreback

pandas/tests/test_graphics.py

@@ -2222,6 +2222,9 @@ def test_hist_colors(self):
 
     @slow
     def test_kde_colors(self):
+        tm._skip_if_no_scipy()
+        _skip_if_no_scipy_gaussian_kde()
+
         from matplotlib import cm
 
         custom_colors = 'rgcby'