HydrostaticHalo test script error

The HydrostaticHalo test_energy_conservation.py script crashes with the following message

Plotting energy as a function of time
Traceback (most recent call last):
  File "test_energy_conservation.py", line 27, in <module>
    v_c = float(params.attrs["SoftenedIsothermalPotential:vrot"])
  File "/usr/lib/python2.7/dist-packages/h5py/_hl/attrs.py", line 48, in __getitem__
    attr = h5a.open(self._id, self._e(name))
  File "h5a.pyx", line 74, in h5py.h5a.open (h5py/h5a.c:2107)
KeyError: "can't open attribute (Attribute: Can't open object)"

On a related note: the other plot scripts for that test use the standard matplotlib backend, which is not very SSH friendly.