fence: Support for power cycle in fence ipmi
    
    Default behaviour (off/get status/on) doesn't work on
    some IPMI implementations, because chasiss power off will
    turn off IPMI management card. Next power on cannot be
    done automatically. But it looks, like chassis power cycle
    is supported and do what we need -> reset machine.
    
    Patch add support for -M (method) option, which can have
    values:
    - onoff - default old behaviour
    - cycle - use new power cycle
    
    rhbz#482913