Revert "remove max connection age"

This reverts commit b9b684194f.

weed/pb/grpc_client_server.go

@@ -46,8 +46,9 @@ func NewGrpcServer(opts ...grpc.ServerOption) *grpc.Server {
 	var options []grpc.ServerOption
 	options = append(options,
 		grpc.KeepaliveParams(keepalive.ServerParameters{
-			Time:    10 * time.Second, // wait time before ping if no activity
-			Timeout: 20 * time.Second, // ping timeout
+			Time:             10 * time.Second, // wait time before ping if no activity
+			Timeout:          20 * time.Second, // ping timeout
+			MaxConnectionAge: 10 * time.Hour,
 		}),
 		grpc.KeepaliveEnforcementPolicy(keepalive.EnforcementPolicy{
 			MinTime:             60 * time.Second, // min time a client should wait before sending a ping