NFSv4/pNFS: Retry the layout return later in case of a timeout or reboot

If the layout return failed due to a timeout or reboot, then leave the
layout segments on the list so that the layout return gets replayed
later.
The exception would be if we're freeing the inode.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>