helm install apisix 连接外部etcd https方式失败

- etcd V3
- k8s 1.18.10
- apisix charts 0.7.2

1.外部etcd https访问方式
ETCDCTL_API=3 etcdctl \
--endpoints=http://192.168.2.202:2379 \
--cacert=/etc/kubernetes/ca/ca.pem \
--cert=/etc/kubernetes/ca/etcd/etcd.pem \
--key=/etc/kubernetes/ca/etcd/etcd-key.pem \
endpoint health

2. 创建 secret
kubectl create secret tls etcd-ssl-s -n ops \
--cert=/etc/kubernetes/ca/etcd/etcd.pem \
--key=/etc/kubernetes/ca/etcd/etcd-key.pem \
--dry-run -o yaml > etcd-ssl-s.yaml

3. helm安装apisix
helm install apisix apisix-072/ --namespace ops \
--set etcd.enabled=false \
--set etcd.host={https://192.168.2.202:2379} \
--set etcd.auth.tls.enabled=true \
--set etcd.auth.tls.existingSecret=etcd-ssl-s \
--set etcd.auth.tls.certFilename=etcd.pem \
--set etcd.auth.tls.certKeyFilename=etcd-key.pem

报错：
usr/local/openresty/luajit/bin/luajit ./apisix/cli/apisix.lua init

WARNING: using fixed Admin API token has security risk.
Please modify "admin_key" in conf/config.yaml .

/usr/local/openresty/luajit/bin/luajit ./apisix/cli/apisix.lua init_etcd
Warning! Request etcd endpoint 'https://192.168.2.202:2379/version' error, error loading private key (No such file or directory), retry time=1
request etcd endpoint 'https://192.168.2.202:2379/version' error, error loading private key (system lib)
Warning! Request etcd endpoint 'https://192.168.2.202:2379/version' error, error loading private key (system lib), retry time=2

Reproduce the helm install command with the external HTTPS etcd configuration and the generated etcd-ssl-s.yaml secret. Start at the apisix.lua init_etcd entry point and inspect the reported private-key loading error. Done means APISIX initializes successfully and connects to the external etcd endpoint without the retry errors.

Written by the indexing model from the issue text.