build_image: restorecon for /usr/local and /mnt/stateful_partition

BUG=b:116072767
TEST=build_images

Change-Id: I428c989f6e2dd38487f59a0bee83c0e20cfbdc1f
Reviewed-on: https://chromium-review.googlesource.com/1423944
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Qijiang Fan <fqj@google.com>
Reviewed-by: Kenny Root <kroot@google.com>
diff --git a/build_library/selinux_util.sh b/build_library/selinux_util.sh
index 2a0d85c..b2382f8 100644
--- a/build_library/selinux_util.sh
+++ b/build_library/selinux_util.sh
@@ -25,5 +25,9 @@
   # of skipping it.
   sudo umount "${rootfs}/var"
   sudo /sbin/setfiles -m -r "${rootfs}" "${file_contexts}" "${rootfs}"
+  sudo /sbin/setfiles -m -r "${rootfs}" "${file_contexts}" "${rootfs}/usr/local"
+  # use ${rootfs}/mnt/stateful_partition instead of ${stateful} in comply with
+  # -r ${rootfs} options.
+  sudo /sbin/setfiles -m -r "${rootfs}" "${file_contexts}" "${rootfs}/mnt/stateful_partition"
   sudo mount --bind "${stateful}/var_overlay" "${rootfs}/var"
 }