Bug in linux/ubuntu/hyperv-gen2.sh script on Ubuntu Server 18.04.1

[iraqigeek]

Hi,

I've tried to build the ubuntu 18.04 server box on hyper-v, and the path and filename for bootx64.efi are not correct.

The correct script is (note the difference in case):
cp -r /boot/efi/EFI/ubuntu/ /boot/efi/EFI/BOOT
mv /boot/efi/EFI/BOOT/ubuntu/shimx64.efi /boot/efi/EFI/BOOT/BOOTX64.efi

Don't know if this breaks the build for other versions of Ubuntu. Tested only on 18.04.1-server-amd64 ISO.