Correcting random amount of gold in gold piles

In original H3 allowed amounts of gold in treasure piles are multipliers of 100. Before this fix gold amount can be any value from range 500-1000.

lib/mapObjects/MiscObjects.cpp

@@ -868,7 +868,7 @@ void CGResource::initObj(CRandomGenerator & rand)
 		switch(subID)
 		{
 		case 6:
-			amount = rand.nextInt(500, 1000);
+			amount = rand.nextInt(5, 10) * 100;
 			break;
 		case 0: case 2:
 			amount = rand.nextInt(6, 10);