Matplotlib does not display hatching when rendering to pdf in fill_between

Hi,

using fill_between with hatching and specifying a edgecolor and color='none' should result in edge and hatch plotted with edgecolor

While the edge is plotted, the hatch is not plotted at all (or not visible) when output is a pdf.
This works for png output.

I assume this is a bug, since it does not occur for the fill() method

PNG 
![test](https://f.cloud.github.com/assets/1030408/819552/e21bf444-efb3-11e2-9050-b82f107b5f1c.png)
PDF
![testpdf](https://f.cloud.github.com/assets/1030408/819571/2725dcc6-efb4-11e2-8e8e-7518053f81d3.png)

Working example:

import matplotlib.pyplot as plt

plt.fill_between([1,2,3],[0.5,0.5,0.5],[1.5,1.5,1.5], hatch='/', color='none', edgecolor='blue')

plt.savefig('test.png')
plt.savefig('test.pdf'')