configmanager: synchronize disk access

runelite-client/src/main/java/net/runelite/client/config/ConfigManager.java

@@ -170,7 +170,7 @@ public class ConfigManager
 		}
 	}
 
-	private void loadFromFile()
+	private synchronized void loadFromFile()
 	{
 		properties.clear();
 
@@ -216,7 +216,7 @@ public class ConfigManager
 		}
 	}
 
-	private void saveToFile() throws IOException
+	private synchronized void saveToFile() throws IOException
 	{
 		propertiesFile.getParentFile().mkdirs();