olapy: use a simpler recipe to create dir

referencing slapos.cookbook:mkdirectory tries to install lxml before
slapos-cookbook part is installed, so the egg build script do not use
slapos libxml2.

component/olapy/buildout.cfg

@@ -19,13 +19,12 @@ setup-eggs =
   ${lxml-python:egg}
   pip
 
-[olapy-dir]
-recipe = slapos.cookbook:mkdirectory
-directory = ${buildout:parts-directory}/olapy/
+[olapy-data-dir]
+recipe = z3c.recipe.mkdir
 
 [olapy-env]
 <= numpy-env
-OLAPY_PATH = ${olapy-dir:directory}
+OLAPY_PATH = ${olapy-data-dir:paths}
 
 [olapy]
 recipe = zc.recipe.egg:custom
@@ -37,4 +36,4 @@ setup-eggs =
   pip
 initialization =
   import os
-  os.environ['OLAPY_PATH'] = "${olapy-dir:directory}"
+  os.environ['OLAPY_PATH'] = "${olapy-data-dir:paths}"