ipv6: Fix inet6_init() cleanup order

Commit 6d0bfe22
	net: ipv6: Add IPv6 support to the ping socket

introduced a change in the cleanup logic of inet6_init and
has a bug in that ipv6_packet_cleanup() may not be called.
Fix the cleanup ordering.

CC: Hannes Frederic Sowa <hannes@stressinduktion.org>
CC: Lorenzo Colitti <lorenzo@google.com>
CC: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>