Purging a specific empty folder does nothing

[kf6kjg]

This occurs on both MySQL, tested here at home, and Cassandra-based grids, tested on the live InWordlz grid.

Here's how to test:

1. Create a new folder in your inventory. It will be named "New Folder".
2. Delete the new folder.
3. Observe that the "delete" has moved the folder to the Trash, and the "New Folder" is sitting right at the top. This is correct and expected.
4. Right-click on the "New Folder" sitting in the Trash and select "Purge Item".
5. Observe that the folder disappears from your inventory. This is correct and expected: the client removes the folder from its own view of inventory.
6. Relog.
7. Open Inventory and expand your Trash folder.
8. Observe to see if the "New Folder" is in the Trash.

If step 8 shows the "New Folder", then the bug is still in effect.

Replicated with the following setup:

Firestorm 4.7.3 (47323) Aug 17 2015 18:14:04 (Firestorm-Releasex64) with OpenSimulator support

You are at 145.0, 138.0, 19.8 in Nargo located at vm-1-4.inworldz.com (198.61.243.4:9035)
SLURL: http://places.inworldz.com/Nargo/145/138/20
(global coordinates 250769.0, 255370.0, 19.8)
InWorldz 0.9.17 R5720

Side note: I'm not sure why I'm in this region, it's just where I happened to be when I logged in. If you have a better place for me to do testing, please let me know!

(Side note 2: this is a fork of issue #23, as that issue was found to be covering at least 3 different problems at the same time.)

[kf6kjg]

Do you realize how much duplicate code there is in here?!

After much discussion with Vin, we both agree that the OnRemoveInventoryFolder event and OnPurgeInventoryDescendents event should be refactored to reuse related code. I'm NOT going to do that right now, but just noting that it should probably be done.