Buffer line when looking for startup message.
Buffer line when looking for startup message.

Speculative fix for #1066.

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