added another convenience method.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@32396 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/util/IOUtils.java

@@ -14,6 +14,14 @@ import java.io.OutputStream;
  * @since 1.337
  */
 public class IOUtils extends org.apache.commons.io.IOUtils {
+    /**
+     * Drains the input stream and closes it.
+     */
+    public static void drain(InputStream in) throws IOException {
+        copy(in,new NullStream());
+        in.close();
+    }
+
     public static void copy(File src, OutputStream out) throws IOException {
         FileInputStream in = new FileInputStream(src);
         try {