when booting from ZFS turned out to also cause the boot path not being
adjusted if booting from CD-ROM with firmware versions that do not employ
the "cdrom" alias in that case. So shuffle the code around instead in order
to achieve the original intent. Ideally, we shouldn't fiddle with the boot
path when booting from UFS on a disk either; unfortunately, there doesn't
seem to be an universal way of telling disks and CD-ROMs apart, though. [1]
- Use NULL instead of 0 for pointers.
PR: 179289
MFC after: 1 week
2fbad3a135