Code review comment for lp:~allenap/maas/ipmi-power-confusion--bug-1560830

Okay, my code is a little too defensive here. Worrying about whether different versions of ipmipower might use "$hostname: $status" or just "$status" is not really warranted because we control the version of ipmipower. It might matter if we were to backport this change, but we won't because the fix already exists in 1.9.

I'll update this code to more closely resemble the fix in 1.9. It won't be the same because so much else has changed in the IPMI driver since, but it will be close enough that our future selves won't see a discrepancy.