deprecation warning with Matplotlib-2.0.0b4 / Holoviews-1.6.2

[stonebig]

Hi,
I get this deprecation warning with Matplolib-2.0.0b4 Holoviews 1.6.2

import holoviews as hv
%load_ext holoviews.ipython
fractal = hv.Image(image)

((fractal * hv.HLine(y=0.16)).hist() + fractal.sample(y=0.16))

C:\WinPython\basedir35\buildQt5\winpython-64bit-3.5.x.3\python-3.5.2.amd64\lib\site-packages\holoviews\plotting\mpl\element.py:152: MatplotlibDeprecationWarning: The set_axis_bgcolor function was deprecated in version 2.0. Use set_facecolor instead.
  axis.set_axis_bgcolor(self.bgcolor)

[stonebig]

https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/axes/_base.py#L2712..L2726

[jlstevens]

Thanks for reporting this and thanks for submitting a PR!

I haven't personally tried out the matplotlib 2.0 beta yet though it is definitely we need to test properly soon.

[philippjfr]

Just merged the PRs. Thanks for making those fixes, closing.