Remove unused import.

Author: iluwatar

tolerant-reader/src/main/java/com/iluwatar/RainbowFishSerializer.java

@@ -1,7 +1,6 @@
 package com.iluwatar;
 
 import java.io.FileInputStream;
-import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.ObjectInputStream;