Unused import.

Author: Marcelo Vanzin

launcher/src/main/java/org/apache/spark/launcher/LauncherConnection.java

@@ -20,7 +20,6 @@
 import java.io.Closeable;
 import java.io.EOFException;
 import java.io.IOException;
-import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.net.Socket;
 import java.util.logging.Level;