roachtest: Use internal IP address for kafka-auth test certs

For these tests, kafka and cockroach live on the same machine, so we
use the InternalIP to create the CHANGEFEED. Previously, however, we
were creating certificates with subject alternative names that used
the external IP, causing connection issues.

While here, I've also removed the advertised listeners config which we
aren't really using for these tests.

Release note: None

pkg/cmd/roachtest/cdc.go

@@ -925,7 +925,6 @@ ssl.keystore.location=%s
 ssl.keystore.password=%s
 
 listeners=PLAINTEXT://:9092,SSL://:9093,SASL_SSL://:9094
-advertised.listeners=PLAINTEXT://%s:9092,SSL://%s:9093,SASL_SSL://:9094
 
 sasl.enabled.mechanisms=SCRAM-SHA-256,SCRAM-SHA-512,PLAIN
 sasl.mechanism.inter.broker.protocol=PLAIN
@@ -995,7 +994,7 @@ func (k kafkaManager) install(ctx context.Context) {
 
 func (k kafkaManager) configureAuth(ctx context.Context) *testCerts {
 	k.c.status("generating TLS certificates")
-	kafkaIP := k.c.ExternalIP(ctx, k.nodes)[0]
+	kafkaIP := k.c.InternalIP(ctx, k.nodes)[0]
 
 	testCerts, err := makeTestCerts(kafkaIP)
 	if err != nil {
@@ -1028,8 +1027,6 @@ func (k kafkaManager) configureAuth(ctx context.Context) *testCerts {
 		keystorePassword,
 		keystorePath,
 		keystorePassword,
-		kafkaIP,
-		kafkaIP,
 	)
 
 	k.PutConfigContent(ctx, testCerts.KafkaKey, kafkaKeyPath)