icmpv6_send() calls ip6_push_pending_frames() indirectly.
Both ip6_push_pending_frames() and icmpv6_send() increment
counter ICMP6_MIB_OUTMSGS.

This patch remove the increment from icmpv6_send.
Signed-off-by: NWang Chen <wangchen@cn.fujitsu.com>
Acked-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>