Beginning with OneFS 5.0, OneFS uses a 64-bit, multiprocessor kernel on
hardware platforms which support it.  This kernel is installed in
/boot/kernel.amd64.  Older nodes continue to use a 32-bit, uniprocessor kernel,
which is installed in /boot/kernel.i386.

Due to various quirks of isi_reimage, isi update, et al., /boot/kernel/kernel
is required to be present in the install.tar and the / file system. However,
it only needs to contain the OneFS kernel version string.  See bug 38568.
