notification.json is empty if lastVersion contains a variant group

[wspee]

Environment

Filter server with:

• Sitecripts: f85775239239
• Infrastructure: 95ca18258f78

Chrome 61 ABP 1.13.4

How to reproduce

1. Create and push the following notification to the filter server:

severity = information

[1]
title.en-US = Test
message.en-US = Test
sample = 1

2. Start the browser and let ABP download the notification.
3. Disable the previously created notification and add a new notification with the content from above.
4. Let ABP download the notification again

Observed behaviour

The server delivers the following notification.json:

{
  "notifications": [],
  "version": "201710041503-4/1"
}

Expected behaviour

The server should deliver the following notification.json:

{
  "notifications": [
    {
      "id": "5",
      "message": {
        "en-US": "Test"
      },
      "severity": "information",
      "title": {
        "en-US": "Test"
      }
    }
  ],
  "version": "201710041504-4/1-5/1"
}

Note

To not break the AB machinery the server is supposed to deliver the same notification he delivered last time. But only if the same notification is still active and it shouldn't affect other notifications.

[wspee]

The old group should be remembered.

[abpbot]

A commit referencing this issue has landed:
​Issue 5827 - Assign new groups even if prior groups are present