fix reboot

 * pkill kill's packer connection itself.
   have no idea how it was ok before

Change-Id: I8acb727b162956d344a326a18ed645edc872b29c
diff --git a/common/ubuntu_reboot.sh b/common/ubuntu_reboot.sh
new file mode 100644
index 0000000..d6790a5
--- /dev/null
+++ b/common/ubuntu_reboot.sh
@@ -0,0 +1,7 @@
+#!/bin/bash -x
+
+touch /run/is_rebooted
+echo 3 > /proc/sys/vm/drop_caches
+sync
+sleep 1
+shutdown -r now