grub_install.sh: Temporarily undo copying the officially signed shim

We previously did the AKV signing in the image job but temporarily
nobbled that code path while we completed the shim review.

Now the AKV signing has been split out into a separate job that will
only be invoked once changes to the jenkins-os repo have been merged.
The only thing we now need to nobble here is copying the signed shim. In
the meantime, we copy the unsigned shim instead. Revert this commit once
the shim review is complete.

build_library/grub_install.sh

@@ -208,7 +208,7 @@ case "${FLAGS_target}" in
             # Official build: Copy signed shim and mm for signing later.
             sudo cp "${BOARD_ROOT}/usr/lib/shim/mm${EFI_ARCH}.efi" \
                 "${ESP_DIR}/EFI/boot/mm${EFI_ARCH}.efi"
-            sudo cp "${BOARD_ROOT}/usr/lib/shim/shim${EFI_ARCH}.efi.signed" \
+            sudo cp "${BOARD_ROOT}/usr/lib/shim/shim${EFI_ARCH}.efi" \
                 "${ESP_DIR}/EFI/boot/boot${EFI_ARCH}.efi"
         fi