sanlock: per command debug logging
    
    Allow debugging logging for specific commands to be
    enabled or disabled at the command processing level.
    
    In sanlock.conf:
    
    debug_cmd = +<name>
    enables cmd level debugging for the named command.
    
    debug_cmd = -<name>
    disables cmd level debugging for the named command.
    
    debug_cmd lines can be repeated, once for each name.
    
    By default sanlock disables some cmds that are often
    repetitive and fill the in-memory debug buffer.