Setup sudo nopassword for initial packer build

Change-Id: I662c8f3fdc26be5c0117e663346ff1d29d60ac0b
Signed-off-by: Mike Marchetti <mmarchetti@sandvine.com>

packer/ubuntu1604-juju.json

@@ -2,12 +2,12 @@
   "provisioners": [
     {
       "type": "shell",
-      "script": "scripts/install_packages.sh"
+      "execute_command": "echo 'vagrant' | {{.Vars}} sudo -S -E bash '{{.Path}}'",
+      "script": "scripts/setup.sh"
     },
     {
       "type": "shell",
-      "execute_command": "echo 'vagrant' | {{.Vars}} sudo -S -E bash '{{.Path}}'",
-      "script": "scripts/setup.sh"
+      "script": "scripts/install_packages.sh"
     },
     {
         "type": "file",