IOUtilsCopyTestCase: remove unused import statement

Author: PascalSchumacher

src/test/java/org/apache/commons/io/IOUtilsCopyTestCase.java

@@ -20,7 +20,6 @@
 import static org.junit.Assert.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.File;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;