Skip tests for ldapsource with python >= 3.7
Until someone works on fixing these, this should make our CI green
again.
I tried to use setupModule() to check for python version, but
pre_setup_database() is apparently called even when a SkipTest exception
is raised there. So handle this in that method.
cubicweb source: source-is-missing cubicweb/web/data/jquery.flot.js line length is * characters (>512)