Stop hard coding i386 as the arch for the build.  Instead, default to the processor we're running on.  Also, supply amd64 version of create_diskimage that's the same as i386's.
Stop hard coding i386 as the arch for the build.  Instead, default to the
processor we're running on.  Also, supply amd64 version of create_diskimage
that's the same as i386's.

# didn't fix the confusion between using the processor for this and using
# the machine (which would be more appropriate).  NANO_ARCH smashes the two
# together right now.

MFC after:	7 days

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