ocfs2: Fix rename/extend race

If one process is extending a file while another is renaming it, there
exists a window when rename could flush the old inode's stale i_size to
disk. This patch recognizes the fact that rename is only updating the old
inode's ctime, so it ensures only that value is flushed to disk.

Signed-off-by: Sunil Mushran <sunil.musran@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>