Skeletons don't cook in a deterministic way

The "Rifle_Skeleton" asset in ShooterGame doesn't cook deterministically, and as such is always included in patches.

Possible regression of [Link Removed]

1. Start with ShooterGame project in 4.15 or 4.16
2. Disable encrypt pak file in project settings
3. Follow the steps in Releasing Your Project
4. Follow the steps in Patching
5. Unpak the .pak file in Saved\StagedBuilds\WindowsNoEditor*projectname*\content\paks with the command UnrealPak.exe pack-name.pak -extract path\to\extract\to\
6. Notice although this file hasn't changed, it is included in the path in the extracted location path\to\extract\to\Engine\Plugins\2D\Paper2D\Content\DummySprite.uexp