[testlib] fix bug in backup file name generation: it may erroneously replace '-' by '_' in database **parent directories**. This should fix random error when test are run under apycot.

if versions_map['cubicweb'][0] == (3, 7, 4):
    config['http-session-time'] *= 60
    config['cleanup-session-time'] *= 60
    config['cleanup-anonymous-session-time'] *= 60