numpy: build without OpenBLAS by default.

you can extend component/numpy/openblas.cfg to build numpy with OpenBLAS.

component/numpy/buildout.cfg

 [buildout]
-
-extends =
-  ../gcc/buildout.cfg
-  ../openblas/buildout.cfg
-
-[numpy-env]
-PATH = ${gcc-fortran:location}/bin:%(PATH)s
-OPENBLAS = ${openblas:location}/lib/libopenblas.so
-LAPACK = ${openblas:location}/lib/libopenblas.so
-ATLAS = ${openblas:location}/lib/libopenblas.so
+parts = numpy
 
 [numpy]
 recipe = zc.recipe.egg:custom
 egg = numpy
-environment = numpy-env
-rpath =
-  ${gcc-fortran:location}/lib
-  ${gcc-fortran:location}/lib64
-  ${openblas:location}/lib

component/numpy/openblas.cfg

+[buildout]
+
+extends =
+  buildout.cfg
+  ../gcc/buildout.cfg
+  ../openblas/buildout.cfg
+
+[numpy-env]
+PATH = ${gcc-fortran:location}/bin:%(PATH)s
+OPENBLAS = ${openblas:location}/lib/libopenblas.so
+LAPACK = ${openblas:location}/lib/libopenblas.so
+ATLAS = ${openblas:location}/lib/libopenblas.so
+
+[numpy]
+environment = numpy-env
+rpath =
+  ${gcc-fortran:location}/lib
+  ${gcc-fortran:location}/lib64
+  ${openblas:location}/lib

component/scipy/buildout.cfg

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