Fix typo in vm_name

Change-Id: I5c3f28659b2a1eeedcc8b0450421047c1ee806cf
Signed-off-by: Michael Marchetti <mmarchetti@sandvine.com>

packer/ubuntu1604-ovf-osm.json

@@ -19,7 +19,7 @@
   "variables": {
     "osm_install_options": "--vimemu",
     "input_ovf": "output-virtualbox-iso/packer-ubuntu-16.04-amd64-juju.ovf",
-    "vm_name": "xenial-osm"
+    "vm_name": "xenial-osm",
     "build_dir": "osm-{{timestamp}}"
   },
   "builders": [