remove cloneTLSConfig, and use (*tls.Config).Clone directly instead.

Author: shogo82148

utils.go

@@ -82,7 +82,7 @@ func DeregisterTLSConfig(key string) {
 func getTLSConfigClone(key string) (config *tls.Config) {
 	tlsConfigLock.RLock()
 	if v, ok := tlsConfigRegistry[key]; ok {
-		config = cloneTLSConfig(v)
+		config = v.Clone()
 	}
 	tlsConfigLock.RUnlock()
 	return
@@ -727,10 +727,6 @@ func (ae *atomicError) Value() error {
 	return nil
 }
 
-func cloneTLSConfig(c *tls.Config) *tls.Config {
-	return c.Clone()
-}
-
 func namedValueToValue(named []driver.NamedValue) ([]driver.Value, error) {
 	dargs := make([]driver.Value, len(named))
 	for n, param := range named {