can we support etcd V2?

[kevinadmin]

when i import etcd v2 into kstone, then status was Unknown.

etcd version
etcd Version: 2.3.4
Git SHA: df60227
Go Version: go1.6.2
Go OS/Arch: linux/amd64

and etcd 2379 port use https, 2380 use http
--initial-advertise-peer-urls "http://xx.xx.xx.xx:2380"
--listen-client-urls 'https://0.0.0.0:2379'

the kstone logs is
E1227 02:07:06.068092 1 helper.go:70] get new clientv3 cfg failed:tls: failed to find any PEM data in certificate input
E1227 02:07:06.068109 1 helper.go:95] failed to get new etcd clientv3,err is tls: failed to find any PEM data in certificate input
I1227 02:07:06.068244 1 event.go:291] "Event occurred" object="kstone/xxx-etcd" kind="EtcdCluster" apiVersion="kstone.tkestack.io/v1alpha1" type="Warning" reason="EtcdClusterUpdateStatus" message="failed to get cluster status tls: failed to find any PEM data in certificate input"
W1227 02:07:06.077150 1 etcdclusters_controller.go:389] cluster xxx-etcd is not ready

[jianhaiqing]

v2 might be deprecated after 3.5. And v2 is default disabled since 3.4.