shared.unattended: Add startup.nsh to RHEL-7 when EFI used

Arm machine uses EFI to boot the machine. To boot grub it requires
startup.nsh file specifying which EFI should be executed. Apparently
this is not done by anaconda, so do this manually if it exists.

NOTE: I'm not sure whether this is the correct way thus I'd like to have
this as a separate commit in case we need to revert.

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>

shared/unattended/RHEL-7-series.ks

@@ -71,5 +71,6 @@ ECHO "update ifcfg-eth0"
 sed -i "/^HWADDR/d" /etc/sysconfig/network-scripts/ifcfg-eth0
 ECHO "Disable lock cdrom udev rules"
 sed -i "/--lock-media/s/^/#/" /usr/lib/udev/rules.d/60-cdrom_id.rules 2>/dev/null>&1
+[ -f /boot/efi/EFI/redhat/grubaa64.efi ] && ECHO "Setup AARCH64 efi" && echo EFI\\redhat\\grubaa64.efi > /boot/efi/startup.nsh
 ECHO 'Post set up finished'
 %end