[yocto] Removal of VM_DEFAULT_KERNEL in Sumo breaks booting initramfs kernel

[Ferry Toth]

We are generating a initramfs kernel and depending on VM_DEFAULT_KERNEL to 
install that into our boot hddimg as vmlinuz, which a U-Boot script looks 
for to load. This works nicely in Rocko.

The patch 'live-vm-common.bbclass: Don't use vmlinuz or VM_DEFAULT_KERNEL' 
for Sumo causes U-Boot to not find vmlinuz. After changing that script to 
load bzImage, kernel won't boot as it has no initramfs.

Is there a better way in Sumo to install bzImage-initramfs-edison.bin 
instead of bzImage to hddimg?

Thanks,
Ferry