- The method introduced as part of r234898 for not altering the boot path   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.
- The method introduced as part of r234898 for not altering the boot path
  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

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase