Generate both armhf and arm64 packages for APT

Change-Id: I1e630d79b20fb29956f5b2326d110623eb5e9edc
diff --git a/kokoro/packages.sh b/kokoro/packages.sh
index ae7862c..8734cf7 100644
--- a/kokoro/packages.sh
+++ b/kokoro/packages.sh
@@ -26,6 +26,11 @@
 sudo apt-get install -y haveged
 sudo /etc/init.d/haveged start
 
-m docker-packages-tarball
+ARCHES="armhf arm64"
+
+for arch in ${ARCHES}
+do
+  USERSPACE_ARCH=${arch} m docker-packages-tarball
+done
 
 cp ${ROOTDIR}/cache/packages.tgz ${KOKORO_ARTIFACTS_DIR}