Fix some warnings that broke the build (inheritDoc doesn't work for @throws?)

Author: nicktindall

server/src/main/java/org/elasticsearch/action/support/PlainActionFuture.java

@@ -66,7 +66,7 @@ public void onFailure(Exception e) {
      *
      * @throws InterruptedException  if the current thread was interrupted before
      *                               or during the call (optional but recommended).
-     * @throws CancellationException {@inheritDoc}
+     * @throws CancellationException if the computation was canceled
      */
     @Override
     public T get(long timeout, TimeUnit unit) throws InterruptedException, TimeoutException, ExecutionException {
@@ -88,7 +88,7 @@ public T get(long timeout, TimeUnit unit) throws InterruptedException, TimeoutEx
      *
      * @throws InterruptedException  if the current thread was interrupted before
      *                               or during the call (optional but recommended).
-     * @throws CancellationException {@inheritDoc}
+     * @throws CancellationException if the computation was canceled
      */
     @Override
     public T get() throws InterruptedException, ExecutionException {