[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.
option_group_changed('port', 'main', 'web')
option_group_changed('query-log-file', 'main', 'web')
option_group_changed('profile', 'main', 'web')
option_group_changed('max-post-length', 'main', 'web')