scikit-learn: fix build with openblas

We also extend 'scipy' because scikit-learn can't be used without it.

component/numpy/buildout.cfg

@@ -6,7 +6,7 @@ extends =
 
 [numpy-env]
 PATH = ${gcc-fortran:location}/bin:%(PATH)s
-BLAS = ${openblas:location}/lib/libopenblas.so
+OPENBLAS = ${openblas:location}/lib/libopenblas.so
 LAPACK = ${openblas:location}/lib/libopenblas.so
 ATLAS = ${openblas:location}/lib/libopenblas.so
 

component/scikit-learn/buildout.cfg

 [buildout]
 extends =
   ../numpy/buildout.cfg
+  ../scipy/buildout.cfg
 
 parts =
   scikit-learn