Use the default registry even without --debug

Previously if the Docker engine was not running the behaviour of
commands would vary depending on whether the --debug flag was provided.

For example, consider `docker logout`:

    $ docker logout
    Not logged in to

-- note the missing server URL

    $ docker --debug logout
    Warning: failed to get default registry endpoint from daemon (Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?). Using system default: https://index.docker.io/v1/
    Not logged in to https://index.docker.io/v1/

-- note the server URL is present

This patch makes only the debug printing conditional on the `--debug` flag,
not the return value.

Signed-off-by: David Scott <dave.scott@docker.com>

cli/command/registry.go

@@ -29,11 +29,16 @@ func ElectAuthServer(ctx context.Context, cli Cli) string {
 	// example a Linux client might be interacting with a Windows daemon, hence
 	// the default registry URL might be Windows specific.
 	serverAddress := registry.IndexServer
-	if info, err := cli.Client().Info(ctx); err != nil && debug.IsEnabled() {
+	if info, err := cli.Client().Info(ctx); err != nil {
+		// Daemon is not responding so use system default.
+		if debug.IsEnabled() {
 			// Only report the warning if we're in debug mode to prevent nagging during engine initialization workflows
 			fmt.Fprintf(cli.Err(), "Warning: failed to get default registry endpoint from daemon (%v). Using system default: %s\n", err, serverAddress)
-	} else if info.IndexServerAddress == "" && debug.IsEnabled() {
+		}
+	} else if info.IndexServerAddress == "" {
+		if debug.IsEnabled() {
 			fmt.Fprintf(cli.Err(), "Warning: Empty registry endpoint from daemon. Using system default: %s\n", serverAddress)
+		}
 	} else {
 		serverAddress = info.IndexServerAddress
 	}