Disallow gaia to change state, i.e., gaia can't be defeated or win

Reviewed By: Freagarach
Differential Revision: D3013
Fixes #5140

This was SVN commit r24064.

binaries/data/mods/public/simulation/components/Player.js

@@ -435,6 +435,12 @@ Player.prototype.SetState = function(newState, message)
 		return;
 	}
 
+	if (!this.playerID)
+	{
+		warn("Gaia can't change state.");
+		return;
+	}
+
 	this.state = newState;
 
 	let won = newState == "won";