App events are not generated when app image is updated using `acorn update --pull` / auto upgrade.

[Sangeetha Hariharan]

Server - main

Steps to reproduce the problem:

Scenario 1:

1. Deploy app using image - image1:v1
2. Make a new version of the image - image1:v1 made available.
3. Update app using acorn update --pull <app-name>
4. This results in app being updated successfully with new version of the image .

There are no events generated for update.

Scenario 2:

1. Deploy app using auto upgrade option - acorn run -n mytestnew --auto-upgrade <image>
2. Make a new version of the image made available.
3. App will get updated with the new version of the image in the next 1 minute.

There are no events generated for this update.

Scenario 3:

1. Deploy app using auto upgrade option - acorn run -n mytestnew --auto-upgrade <image>.v#.#.#
2. Make a image tag that satisfies the auto upgrade format made available.
3. App will get updated with the new image in the next 1 minute.

There are no events generated for this update.

Expected Behavior:
In all the above cases , there needs to be an AppSpecUpdate/AppImagePullSuccess events that gets generated in all the 3 cases.

[Craig Jellick]

Scooted to low