Drop root password from mosk images

Related-Prod: PRODX-3456
Change-Id: Id46d6a1a4595ca3d16c78c7c05c84c2fa59d0063
diff --git a/trymos/image_build/template.json b/trymos/image_build/template.json
index 20d12e1..a6e0c89 100644
--- a/trymos/image_build/template.json
+++ b/trymos/image_build/template.json
@@ -77,7 +77,7 @@
       "ssh_host_port_max": 7050,
       "vnc_port_max": "5956",
       "vnc_port_min": "5956",
-      "shutdown_command": "shutdown -P now",
+      "shutdown_command": "passwd -d root; rm -rf /etc/sudoers.d/90-cloud-init-users; /sbin/shutdown -P now",
       "boot_wait": "10s",
       "ssh_wait_timeout": "360s"
     }