Remove deprecation warning for Go 1.15. (#178)

transport/tlscommon/config.go

@@ -20,13 +20,8 @@ package tlscommon
 import (
 	"crypto/tls"
 	"errors"
-	"sync"
-
-	"github.com/elastic/elastic-agent-libs/logp/cfgwarn"
 )
 
-var warnOnce sync.Once
-
 // Config defines the user configurable options in the yaml file.
 type Config struct {
 	Enabled              *bool                   `config:"enabled" yaml:"enabled,omitempty"`
@@ -97,10 +92,6 @@ func LoadTLSConfig(config *Config) (*TLSConfig, error) {
 // Validate values the TLSConfig struct making sure certificate sure we have both a certificate and
 // a key.
 func (c *Config) Validate() error {
-	warnOnce.Do(func() {
-		cfgwarn.Deprecate("8.0.0", "Treating the CommonName field on X.509 certificates as a host name when no Subject Alternative Names are present is going to be removed. Please update your certificates if needed.")
-	})
-
 	return c.Certificate.Validate()
 }