client: log warning when SecureConfig is nil

Author: fairclothjm

client.go

@@ -547,7 +547,9 @@ func (c *Client) Start() (addr net.Addr, err error) {
 		return nil, err
 	}
 
-	if c.config.SecureConfig != nil {
+	if c.config.SecureConfig == nil {
+		c.logger.Warn("plugin configured with a nil SecureConfig")
+	} else {
 		if ok, err := c.config.SecureConfig.Check(cmd.Path); err != nil {
 			return nil, fmt.Errorf("error verifying checksum: %s", err)
 		} else if !ok {