use MissingParameterValue exception in iboot

The iboot driver raises InvalidParameterValue exception in _parse_driver_info() when any required parameters are missing. It should be raising
MissingParameterValue instead.

Change-Id: I7e8955712c0ef0166a1b4daf1008579413fdfcb1
Closes-Bug: #1358758
Merge "use MissingParameterValue exception in iboot"