Can't add dynamic ports using PUT

[gkleiman]

http DELETE :8080/v2/groups
http POST :8080/v2/apps <<EOF
{
  "id": "/foo",
  "cmd": "sleep 1000",
  "ports": [
      0
  ]
}
EOF
http PUT :8080/v2/apps <<EOF
[
  {
    "id": "/foo",
    "cmd": "sleep 1000",
    "ports": [
        0,
        0
    ]
  }
]
EOF

Results in the following instead of in a app with 2 dynamic ports:

{
  "message": "Object is not valid",
  "details": [
    {
      "attribute": "apps[0].ports",
      "error": "Elements must be unique"
    }
  ]
}