stack/slapos: use statsmodels 0.8.0 on python2

0.11.1 is not compatible with the version of numpy we are using on
python2:

  File "SR/develop-eggs/statsmodels-0.11.1-py2.7-linux-x86_64.egg/statsmodels/compat/numpy.py", line 46, in <module>
    NP_LT_114 = LooseVersion(np.__version__) < LooseVersion('1.14')
AttributeError: 'module' object has no attribute '__version__'

component/jupyter-py2/buildout.cfg

@@ -71,7 +71,6 @@ notebook = 4.4.1
 prompt-toolkit = 1.0.13
 pyzmq = 16.0.2
 scikit-learn = 0.18.1
-statsmodels = 0.8.0
 terminado = 0.6
 tornado = 4.4.2
 

stack/slapos.cfg

@@ -362,6 +362,7 @@ requests = 2.27.1
 selectors34 = 1.2
 smmap = 0.9.0
 smmap2 = 2.0.5
+statsmodels = 0.8.0
 traitlets = 4.3.3
 Werkzeug = 1.0.1
 wheel = 0.35.1:whl