Unused paramters introduced by https://github.com/netty/netty/pull/4257

Motivation:
PR https://github.com/netty/netty/pull/4257 introduced paramters and didn't use them.

Modifications:
- Use the new paramters

Result:
No warnings and correct behavior

handler/src/main/java/io/netty/handler/ssl/util/SelfSignedCertificate.java

@@ -84,7 +84,7 @@ public final class SelfSignedCertificate {
      * @param notAfter Certificate is not valid after this time
      */
     public SelfSignedCertificate(Date notBefore, Date notAfter) throws CertificateException {
-        this("example.com");
+        this("example.com", notBefore, notAfter);
     }
 
     /**