Blueprint dirty after PIE if blueprint contains a reroute node for a Key Struct

If a blueprint contains a reroute node for a key structure it will cause the blueprint to become dirtied (needs to be compiled) upon exiting PIE.

1. Open the editor
2. Create a new blueprint
3. Add a left mouse button event to the event graph
4. Drag off of the "Key" pin and add an Equivalence (==) node
5. Observe Blueprint Compiles
6. Add a reroute node between Key and ==
7. Observe Blueprint stays dirty

"Key Structure" reroute nodes cause compilation problems