- Fix a bug which does not return ICMPv6 "packat too big" error   message when DF flag is set. - Calculate an ipv6 packet size including fragment header when DF flag   is not set.
- Fix a bug which does not return ICMPv6 "packat too big" error
  message when DF flag is set.
- Calculate an ipv6 packet size including fragment header when DF flag
  is not set.

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame