/kind bug

/sig network

when start service kube-proxy
/var/log/message :
I0129 19:40:03.709536 21148 iptables.go:381] running iptables-restore [-w5 -T nat --noflush --counters]
E0129 19:40:03.712093 21148 proxier.go:792] Failed to execute iptables-restore for nat: exit status 1 (iptables-restore: invalid option -- '5'
iptables-restore: line 7 failed
)

And i run command

iptables-restore -w5
iptables-restore: invalid option -- '5'

then run comman with arg value split by space

iptables-restore -w 5

no error output.
I'm worried about the iptables-restore will not execute because of this error.
Please fix it, thanks a lot.

Environment:

• Kubernetes version (use kubectl version):v1.9.2
• Cloud provider or hardware configuration:None
• OS (e.g. from /etc/os-release):CentOS Linux release 7.4.1708 (Core)
• Kernel (e.g. uname -a):3.10.0-693.11.6.el7.x86_64 Unit test coverage in Kubelet is lousy. (~30%) #1 SMP Thu Jan 4 01:06:37 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
• Install tools: binary install
• Others: