[Rseding91] *[0.13.3] Campaign difficulty always easy

[CyberPhantom]

Description:
The campaign difficulty is always set to Easy, even if the user starts the campaign on Normal or Hard. (This applies to both the New Hope and Tight Spot campaigns.)

Steps to Reproduce:
1. Start a campaign that has difficulty settings: New Hope or Tight Spot
2. Select either Normal or Hard as the difficulty
3. Check the game difficulty setting via the console or load screen:
- game.player.print(game.difficulty) prints 0 (easy)
- Save the game then open the Load Game GUI and look at the Difficulty listed for that save. It says Easy.

Affected versions:
Tested in Steam Factorio Win64 0.13.2 and 0.13.3. Both are affected.
0.12.35 worked properly.

[Loewchen]

Can confirm.
Thx for the detailed report

[Rseding91]

fixed for 0.13.9.