Remove remnants of config loading in credentials routine

main.go

@@ -40,11 +40,9 @@ func (c *TokenCache) Credentials() (*google.Credentials, error) {
 			return nil, fmt.Errorf("could not read credentials: %v", err)
 		}
 		c.CredentialData, err = google.CredentialsFromJSON(context.Background(), data, c.CredentialScopes...)
-		err = json.NewDecoder(f).Decode(&c.ConfigData)
 		if err != nil {
-			return nil, fmt.Errorf("could not decode config: %v", err)
+			return nil, fmt.Errorf("could not decode credentials: %v", err)
 		}
-		c.configLoaded = true
 	}
 	return c.CredentialData, nil
 }