[matplotlib-devel] radial grids broken on polar?

When plotting the polar demo, I am not getting radial grids on the
trunk (but I am getting them on the branch).  Any ideas?

import matplotlib
import numpy as np
from matplotlib.pyplot import figure, show, rc, grid

# radar green, solid grid lines
rc('grid', color='#316931', linewidth=1, linestyle='-')
rc('xtick', labelsize=15)
rc('ytick', labelsize=15)

# force square figure and square axes looks better for polar, IMO
width, height = matplotlib.rcParams['figure.figsize']
size = min(width, height)
# make a square figure
fig = figure(figsize=(size, size))
ax = fig.add_axes([0.1, 0.1, 0.8, 0.8], polar=True, axisbg='#d5de9c')

r = np.arange(0, 3.0, 0.01)
theta = 2*np.pi*r
ax.plot(theta, r, color='#ee8d18', lw=3)
ax.set_rmax(2.0)

ax.set_rgrids(np.arange(0.5, 2.0, 0.5))
ax.grid(True)

ax.set_title("And there was much rejoicing!", fontsize=20)
show()