#10 crash on Easy/Hardest difficulties

[Patrick Horn]

The vegastrike.config in Privateer Gold defines the "ai_directory" variable differently depending on the difficulty setting.

On easy, it sets it to "ai.easy", and on hardest it sets it to "ai.hard", while only on medium difficulty it uses the correct "ai" folder.

It turns out that neither of those directories exist, so when it loads an AI ship (usually within two autopilots), it looks for the "default.agg.xml" file in "ai.easy" or "ai.hard" and crashes.

This crash did not happen on older versions (Privateer Remake) because it actually had scripts in ai.easy and ai.hard