build_image: always specify filesystem type for mount

build_image

Index: build_image
diff --git a/build_image b/build_image
index c54013bc4e6a58374fea4945e8a67ee4078b0c95..83460eb2c3a13c410a47dc4dd8746fa11b781177 100755
--- a/build_image
+++ b/build_image
@@ -569,7 +569,7 @@ create_base_image() {
                -e remount-ro \
                 "${LOOP_DEV}"
   # TODO(wad) call tune2fs prior to finalization to set the mount count to 0.
-  sudo mount "${LOOP_DEV}" "${ROOT_FS_DIR}"
+  sudo mount -t ext2 "${LOOP_DEV}" "${ROOT_FS_DIR}"
 
   # Create stateful partition of the same size as the rootfs.
   STATEFUL_LOOP_DEV=$(sudo losetup -f)
@@ -587,7 +587,7 @@ create_base_image() {
   sudo losetup "${STATEFUL_LOOP_DEV}" "${STATEFUL_FS_IMG}"
   sudo mkfs.ext3 "${STATEFUL_LOOP_DEV}"
   sudo tune2fs -L "${DISK_LABEL}" -U "${UUID}" -c 0 -i 0 "${STATEFUL_LOOP_DEV}"
-  sudo mount "${STATEFUL_LOOP_DEV}" "${STATEFUL_FS_DIR}"
+  sudo mount -t ext3 "${STATEFUL_LOOP_DEV}" "${STATEFUL_FS_DIR}"
 
   # -- Install packages into the root file system --