calico/node: Makefile, always pull alpine
calico/node: Makefile, always pull alpine

To ensure that latest alpine release is used

projectcalico/calico-containers,Metaswitch/calico-docker,projectcalico/calico-containers,projectcalico/calico-containers,projectcalico/calico-docker,Metaswitch/calico-docker,projectcalico/calico-docker,insequent/calico-docker,insequent/calico-docker