Code review comment for lp:~newell-jensen/maas/fix-1690781

It's really weird that you couldn't reproduce this.

If qemu-system-x86 package is not installed, there should be no /usr/bin/qemu-system-x86_64 emulator binary, and that's what domcapabilities uses to check for domain capabilities (or whatever architecture you've got if it's not x86_64).

I'll confirm this fixes it, though I fully suspect it does.

I'd also prefer a fix were self.run() raises an exception when the return code is not 0, but that would probably be a much bigger change that's not suitable for upcoming 2.2.

(I've added another review slot for myself since Andres mentioned that he wants others to confirm our reviews too)