Prompt CNI version to v0.7.1.
Prompt CNI version to v0.7.1.

Due to the hostPort does not work because of issue
https://github.com/containernetworking/plugins/pull/81 , it is
better to upgrade CNI to 0.7.3 to fix this, this can also improve
the portmap performance.

projectcalico/calico-rkt,projectcalico/calico-cni,projectcalico/calico-cni,projectcalico/calico-cni