Add note about alternative to lena

Author: jenshnielsen

doc/api/api_changes/2015-08-16_remove_lena_from_sample_data.rst

@@ -3,4 +3,6 @@ Removed `Lena` images from sample_data
 
 The lena.png and lena.jpg images have been removed from matplotlibs sample_data 
 directory. The images are also no longer available from 
-`matplotlib.cbook.get_sample_data`
+`matplotlib.cbook.get_sample_data`. We suggest usinge
+`matplotlib.cbook.get_sample_data('grace_hopper.png')` or
+`matplotlib.cbook.get_sample_data('grace_hopper.jpg')` instead.