Tweak peb to powercycle fiber-USB convertor ("usb2")

While troubleshooting PFI old E-box, it was found that one of the fiber-USB convertor (usb2) was always on, because it is connected to different port (flow = boardb) of the PDU. As the current pebActor only has "bounce" option for "boardb" we need to send raw command (see below),or power-cycle the whole PFI E-box, in order to intentionally turn off and on the usb2. 

oneCmd.py peb power raw=:S1FC017C0
oneCmd.py peb power raw=:S1FC01FC0

To powercycle both usb convertors rather simply, it would be nice to tweak the software. In longer-term, the PDU board and the wiring of the old E-box will be fixed.