pxeboot_setup.sh copies wrong grubx64.efi

Description
-----------
Secure boot fails for load setup with pxeboot_setup.sh.

umount /media/iso
mount -o loop bootimage.iso /media/iso
mount -o remount,exec,dev /media/iso
/media/iso/pxeboot_setup.sh -u http://147.11.88.7/tftp -t /srv/tftp/

Resulted in:

error: vmlinuz has invalid signature.
error: you need to load the kernel first.

Press any key to continue...

Severity
--------
Minor

Steps to Reproduce
------------------
PXE boot controller-0 with secure boot enabled from a PXE server by running the pxeboot_setup.sh from the ISO.

Expected Behavior
-----------------
PXE boot completes when using the pxeboot_setup.sh script when secure boot is enabled.

Actual Behavior
---------------
Signature failure.

Reproducibility
---------------
Reproducible.

System Configuration
--------------------
PXE boot a controller-0, single node.

Branch/Pull Time/Commit
-----------------------
starlingx/master

Workaround
----------
pxeboot_setup.sh is copying grubx64.efi from /media/iso/pxeboot/EFI/grubx64.efi instead of /media/iso/EFI/BOOT/grubx64.efi. Manually fixing the copy after running the script allowed PXE boot with secure boot enabled.