BugLink: http://bugs.launchpad.net/bugs/1745047

[ Upstream commit f859b4af ]

After parsing the sit netlink change info, we forget to update frag_off in
ipip6_tunnel_update(). Fix it by assigning frag_off with new value.
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>