POST to /api/groups/ID with NULL filter doesn't clear the filter

[jrafanie]

1. GET:
   http://localhost:3000/api/groups/31/?expand=resources&attributes=description,entitlement.filters

Result:

{
  "href": "http://localhost:3000/api/groups/31",
  "description": "joe",
  "id": "31",
  "entitlement": {
    "filters": {
      "belongsto": ["/belongsto/ExtManagementSystem|VMware-infrastructure/EmsFolder|Datacenters/EmsFolder|XXX/EmsFolder|datastore"],
      "managed": [["/managed/cc/001"]]
    }
  }
}

2. POST
   http://localhost:3000/api/groups/31/

BODY:

{
  "action" : "edit",
  "resource" : {
    "filters" : null
  }
}

3. Do the GET in 1) again, and the filters remain

4. If you do the POST in 2) but with an empty [] filter, see below, it will work. null does not work.

BODY:

{
  "action" : "edit",
  "resource" : {
    "filters" : {
      "belongsto": [],
      "managed": [[]]
    }
  }
}

[jrafanie]

Note, the above POST leads to an update({}) with an empty hash as data doesn't contain anything since the filters is nil. This is another workaround:

POST /api/groups/37/
{
  "action" : "edit",
  "resource" : {
    "filters" : {}
  }
}