[test] Add user-site to PYTHONPATH before installation of new cube in test_newcube_install Otherwise, setuptools complains that the target installation directory (i.e. "user site" is not in PYTHONPATH). This is probably because we use a fake HOME with --user install option. Failure shows up when running tests through tox without system site packages (see next patch).

for rtype in ('cw_support', 'cw_dont_cross', 'cw_may_cross'):
    drop_relation_type(rtype)

if not 'url' in schema['CWSource'].subjrels:
    add_attribute('CWSource', 'url')
    add_attribute('CWSource', 'parser')
    add_attribute('CWSource', 'latest_retrieval')