Crash when converting versions adds a neuron with a duplicate description

For example, in 0.6, the "EggProduction" output neuron was added. So if I...

1. Create an 0.5 brain with a hidden neuron whose description is "EggProduction"
2. Try to save that brain to an 0.6 bibite

Expected: I get prompted about the duplicate description and asked if I want to fix it, just like when loading a bibite
What happens: Crash!