ASM-2791 fix for deployment without integrated raid

check_for_important_attrs assumed that for HDD deployments the
IntegratedRaid BIOS parameter must be available and raised an
exception otherwise. However that is not valid for servers that
only have slot RAID.
Merge pull request #101 from gavin-scott/asm-2791-8.0.0

ASM-2791 fix for deployment without integrated raid