Fix Grub configurations for Fedora images built on a UEFI host.

The grub install scripts on Fedora have hardcoded checks for
/sys/firmware/efi and if the directory exists, it uses efi
specific instruction like initrdefi, linuxefi etc. vm element
should fix it once the configuration is generated.

Closes-bug: #1231946
Change-Id: I888304cb9167b8e074b04ca6c5b2f9143b70d37d

elements/vm/finalise.d/51-bootloader

@@ -171,6 +171,10 @@ function install_grub2 {
       if [ $(lsb_release -rs) = '19' ]; then
         sed -i "s%UUID=[A-Za-z0-9\-]*%LABEL=cloudimg-rootfs%" /etc/fstab
       fi
+      # Fix efi specific instructions in grub config file
+      if [ -d /sys/firmware/efi ]; then
+          sed -i 's%\(initrd\|linux\)efi /boot%\1 /boot%g' $GRUB_CFG
+      fi
     fi
 }