use long math when calculating a long

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/io/trunk@1722481 13f79535-47bb-0310-9956-ffa450edef68

Author: mebigfatguy

src/main/java/org/apache/commons/io/FileUtils.java

@@ -1724,7 +1724,7 @@ private static File[] verifiedListFiles(File directory) throws IOException {
      * @throws NullPointerException if the file is {@code null}
      */
     public static boolean waitFor(final File file, final int seconds) {
-        long finishAt = System.currentTimeMillis() + (seconds * 1000);
+        long finishAt = System.currentTimeMillis() + (seconds * 1000L);
         boolean wasInterrupted = false;
         try {
             while (!file.exists()) {