These variables should be unsigned. This fixes sysctl handler for
nf_ct_frag6_{low,high}_thresh.
Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>