Fix wrong scenario name capitalization which broke starting missions (#869)

Author: Metadorius

DXMainClient/DXGUI/Campaign/CampaignSelector.cs

@@ -308,7 +308,7 @@ private void LaunchMission(Mission mission)
             if (copyMapsToSpawnmapINI)
                 spawnIniSettings.AddKey("Scenario", "spawnmap.ini");
             else
-                spawnIniSettings.AddKey("Scenario", scenario.ToUpperInvariant());
+                spawnIniSettings.AddKey("Scenario", scenario);
 
             // No one wants to play missions on Fastest, so we'll change it to Faster
             if (UserINISettings.Instance.GameSpeed == 0)