Fix ready-test for newer etcd versions
Fix ready-test for newer etcd versions

The version quay.io/coreos/etcd:v3.3.11-arm64 outputs the string 'embed: ready to serve client requests'.

ondrej-fabry/vpp-agent,ondrej-fabry/vpp-agent,ondrej-fabry/vpp-agent,VladoLavor/vpp-agent,VladoLavor/vpp-agent,VladoLavor/vpp-agent