Correctly delete SelfSignedCertificate once done with it.

Motivation:

In OpenSsl init code we create a SelfSignedCertificate which we not explicitly delete. This can lead to have the deletion delayed.

Modifications:

Delete the SelfSignedCertificate once done with it.

Result:

Fixes [netty#6716]

handler/src/main/java/io/netty/handler/ssl/OpenSsl.java

@@ -122,6 +122,7 @@ public final class OpenSsl {
                 final long sslCtx = SSLContext.make(SSL.SSL_PROTOCOL_ALL, SSL.SSL_MODE_SERVER);
                 long privateKeyBio = 0;
                 long certBio = 0;
+                SelfSignedCertificate cert = null;
                 try {
                     SSLContext.setCipherSuite(sslCtx, "ALL");
                     final long ssl = SSL.newSSL(sslCtx, true);
@@ -140,7 +141,7 @@ public final class OpenSsl {
                             logger.debug("Hostname Verification not supported.");
                         }
                         try {
-                            SelfSignedCertificate cert = new SelfSignedCertificate();
+                            cert = new SelfSignedCertificate();
                             certBio = ReferenceCountedOpenSslContext.toBIO(cert.cert());
                             SSL.setCertificateChainBio(ssl, certBio, false);
                             supportsKeyManagerFactory = true;
@@ -166,6 +167,9 @@ public Boolean run() {
                         if (certBio != 0) {
                             SSL.freeBIO(certBio);
                         }
+                        if (cert != null) {
+                            cert.delete();
+                        }
                     }
                 } finally {
                     SSLContext.free(sslCtx);