fuse: set stolen page uptodate

Regular pipe buffers' ->steal method (generic_pipe_buf_steal()) doesn't set
PG_uptodate.

Don't warn on this condition, just set the uptodate flag.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org

fs/fuse/dev.c

@@ -890,8 +890,8 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 
 	newpage = buf->page;
 
-	if (WARN_ON(!PageUptodate(newpage)))
-		return -EIO;
+	if (!PageUptodate(newpage))
+		SetPageUptodate(newpage);
 
 	ClearPageMappedToDisk(newpage);