Fix rootfs symlink, symlink sha256sum

Change-Id: Ia5c09f4f67eb6858d831d23e8326a728aab992fa
diff --git a/kokoro/rootfs.sh b/kokoro/rootfs.sh
index 5efedd4..16a4edd 100644
--- a/kokoro/rootfs.sh
+++ b/kokoro/rootfs.sh
@@ -44,4 +44,5 @@
 
 # For now, symlink rootfs_arm64 to rootfs.
 # Remove when nothing depends on rootfs.img existing.
-ln -sf rootfs_arm64.img ${KOKORO_ARTIFACTS_DIR}/rootfs.img
+ln -sf rootfs_arm64.raw.img ${KOKORO_ARTIFACTS_DIR}/rootfs.raw.img
+ln -sf rootfs_arm64.raw.img.sha256sum ${KOKORO_ARTIFACTS_DIR}/rootfs.raw.img.sha256sum