cnitool: add support for CNI_ARGS
cnitool: add support for CNI_ARGS

Signed-off-by: Pengfei Ni <5ba478f7e379e5026033ada2badb07ae28fac367@gmail.com>

rosenhouse/cni,appc/cni,dcbw/cni,containernetworking/cni,containernetworking/cni,dcbw/cni,rosenhouse/cni,kad/cni,appc/cni,kad/cni