try to detect if zope-2.8 flavour or not by the existense of parts/zope-2.8 directory, instead of sys.verison_info, because the applience test suite uses system python, not a python built by buildout.

# BBB it is adhoc, but all tests in this file will be soon merged into
# each buildout configuration. so please do not care.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@41426 20353a03-c40f-0410-a6d1-a30d3c3de9de