There are two goroutines accessing the `gs` grpc server var. Before
insecure `gs` server start, the `gs` can be changed to secure server and
then the client will fail to connect to etcd with insecure request. It
is data-race. We should use argument for reference in the new goroutine.
fix: #15495
Signed-off-by: Wei Fu <fuweid89@gmail.com>
(cherry picked from commit a9988e2625eede1af81d189b5f2ecf7d4af3edf1)
Signed-off-by: Wei Fu <fuweid89@gmail.com>