etcdsever: avoid creating member dir before finishing validate bootstrap

This commit fixes the issue of creating member dir before validating
the configuration. When member dir exists, it indicates the local etcd
process is a valid etcd member. So we should only create member dir
after we finish configuration validation, joining validation or
discovery validation.

etcdserver/server.go

@@ -217,11 +217,6 @@ func NewServer(cfg *ServerConfig) (*EtcdServer, error) {
 		return nil, err
 	}
 
-	err = os.MkdirAll(cfg.MemberDir(), privateDirMode)
-	if err != nil && err != os.ErrExist {
-		return nil, err
-	}
-
 	haveWAL := wal.Exist(cfg.WALDir())
 	ss := snap.New(cfg.SnapDir())
 
@@ -328,6 +323,11 @@ func NewServer(cfg *ServerConfig) (*EtcdServer, error) {
 		return nil, fmt.Errorf("unsupported bootstrap config")
 	}
 
+	err = os.MkdirAll(cfg.MemberDir(), privateDirMode)
+	if err != nil && err != os.ErrExist {
+		return nil, err
+	}
+
 	sstats := &stats.ServerStats{
 		Name: cfg.Name,
 		ID:   id.String(),