fixed Compilation failure

core/src/main/java/hudson/FilePath.java

@@ -2456,7 +2456,7 @@ public final class FilePath implements Serializable {
      * (User's home directory in the Unix sense) of the given channel.
      */
     public static FilePath getHomeDirectory(VirtualChannel ch) throws InterruptedException, IOException {
-        ch.call(new Callable<FilePath,IOException>() {
+        return ch.call(new Callable<FilePath,IOException>() {
             public FilePath call() throws IOException {
                 return new FilePath(new File(System.getProperty("user.home")));
             }