ipv6: Fix leak in ipv6_gso_segment().

commit e3e86b5119f81e5e2499bea7ea1ebe8ac6aab789 upstream.

If ip6_find_1stfragopt() fails and we return an error we have to free
up 'segs' because nobody else is going to.

Fixes: 2423496af35d ("ipv6: Prevent overrun when parsing v6 header options")
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --cc net/ipv6/af_inet6.c
Simple merge