Enhance build_image to support new grub2 1.99+

BUG=chromium-os:21244
TEST=./build_image works with both old and new grub

Change-Id: Idca80f777b7da72da1690bc374a156f910d487b0
Reviewed-on: https://gerrit.chromium.org/gerrit/11876
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Tested-by: Anush Elangovan <anush@chromium.org>
Commit-Ready: Anush Elangovan <anush@chromium.org>

build_library/create_legacy_bootloader_templates.sh

@@ -146,8 +146,17 @@ EOF
 
   # To cover all of our bases, now populate templated boot support for efi.
   sudo mkdir -p "${FLAGS_to}"/efi/boot
+
+  if [[ -f /bin/grub2-mkimage ]];then
+    # Use the newer grub2 1.99+
+    sudo grub2-mkimage -p /efi/boot -O x86_64-efi \
+     -o "${FLAGS_to}/efi/boot/bootx64.efi" \
+     part_gpt fat ext2 hfs hfsplus normal boot chain configfile linux
+  else
+    # Remove this else case after a few weeks (sometime in Dec 2011)
     sudo grub-mkimage -p /efi/boot -o "${FLAGS_to}/efi/boot/bootx64.efi" \
      part_gpt fat ext2 normal boot sh chain configfile linux
+  fi
   # Templated variables:
   #  DMTABLEA, DMTABLEB -> '0 xxxx verity ... '
   # This should be replaced during postinst when updating the ESP.