ceo panic on getMemberHealth

I have found the ceo stuck in the ceo healthcheck giroutine, the logs show as follow: ``` I0223 11:08:21.651819 1 quorumguardcleanupcontroller.go:134] 2/3 guard pods ready. Waiting until all new guard pods are ready panic: send on closed channel goroutine 373196 [running]: github.com/openshift/cluster-etcd-operator/pkg/etcdcli.getMemberHealth.func1() /go/src/github.com/openshift/cluster-etcd-operator/pkg/etcdcli/health.go:58 +0xd2 created by github.com/openshift/cluster-etcd-operator/pkg/etcdcli.getMemberHealth /go/src/github.com/openshift/cluster-etcd-operator/pkg/etcdcli/health.go:54 +0x2b1 ```