-remove unused import

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@542471 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/Concat.java

@@ -29,7 +29,6 @@ import java.io.BufferedReader;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.InputStreamReader;
-import java.io.OutputStreamWriter;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Iterator;