fix build

Signed-off-by: omerlh <omerl@soluto.com>

plugins/discovery/config.go

@@ -75,7 +75,7 @@ func (c *Config) validateAndInjectDefaults(services []string) error {
 func (c *Config) getServiceFromList(service string, services []string) (string, error) {
 	if service == "" {
 		if len(services) != 1 {
-			return nil, fmt.Errorf("more than one service is defined")
+			return "", fmt.Errorf("more than one service is defined")
 		}
 		return services[0], nil
 	}