[test, html validation] make validator selection somewhat smarter (at least it works properly when content is demoted from xhtml to html, making the XMLDemotingValidator class useless

from os.path import join
from cubicweb.toolsutils import create_dir

option_renamed('pyro-application-id', 'pyro-instance-id')

create_dir(join(config.appdatahome, 'backup'))