Matplotlib is broken on beatubulatest.lab

https://gitlab.idiap.ch/bob/bob.measure/builds/10001#build-trace

ERROR: bob.measure.test_scripts.test_compute_perf
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/local/gitlab-runner/builds/6b02994f/0/bob/bob.measure/env/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/local/gitlab-runner/builds/6b02994f/0/bob/bob.measure/env/lib/python2.7/site-packages/bob/measure/test_scripts.py", line 38, in test_compute_perf
    nose.tools.eq_(main(cmdline.split()), 0)
  File "/local/gitlab-runner/builds/6b02994f/0/bob/bob.measure/env/lib/python2.7/site-packages/bob/measure/script/compute_perf.py", line 262, in main
    options.plotfile)
  File "/local/gitlab-runner/builds/6b02994f/0/bob/bob.measure/env/lib/python2.7/site-packages/bob/measure/script/compute_perf.py", line 89, in plots
    import matplotlib.pyplot as mpl
  File "/local/gitlab-runner/builds/6b02994f/0/bob/bob.measure/env/lib/python2.7/site-packages/matplotlib/pyplot.py", line 114, in <module>
    _backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
  File "/local/gitlab-runner/builds/6b02994f/0/bob/bob.measure/env/lib/python2.7/site-packages/matplotlib/backends/__init__.py", line 32, in pylab_setup
    globals(),locals(),[backend_name],0)
  File "/local/gitlab-runner/builds/6b02994f/0/bob/bob.measure/env/lib/python2.7/site-packages/matplotlib/backends/backend_qt4agg.py", line 18, in <module>
    from .backend_qt5agg import FigureCanvasQTAggBase as _FigureCanvasQTAggBase
  File "/local/gitlab-runner/builds/6b02994f/0/bob/bob.measure/env/lib/python2.7/site-packages/matplotlib/backends/backend_qt5agg.py", line 15, in <module>
    from .backend_qt5 import QtCore
  File "/local/gitlab-runner/builds/6b02994f/0/bob/bob.measure/env/lib/python2.7/site-packages/matplotlib/backends/backend_qt5.py", line 31, in <module>
    from .qt_compat import QtCore, QtGui, QtWidgets, _getSaveFileName, __version__
  File "/local/gitlab-runner/builds/6b02994f/0/bob/bob.measure/env/lib/python2.7/site-packages/matplotlib/backends/qt_compat.py", line 124, in <module>
    from PyQt4 import QtCore, QtGui
ImportError: libXrender.so.1: cannot open shared object file: No such file or directory