sanlock: add config setting for logging resource names
    
    sanlock.conf names_log_priority can be used to set the level
    at which each resource name+location is logged.  The default
    level is LOG_WARNING as before, so each requested resource
    name is still saved in sanlock.log.  With some applications,
    this may produce too much data, in which case names_log_priority
    can be set to 7 (LOG_DEBUG).
    
    Also correct the default values in help/man output for
    other settings.