Fix resumption code around when not available

Can't set a ticket if the encryption callback is NULL.
If no useable pre-shared key is found then we won't do PSK.

src/tls.c

@@ -8062,7 +8062,7 @@ int TLSX_PopulateExtensions(WOLFSSL* ssl, byte isServer)
             }
 
         #if defined(HAVE_SESSION_TICKET)
-            if (ssl->options.resuming) {
+            if (ssl->options.resuming && ssl->ctx->ticketEncCb != NULL) {
                 WOLFSSL_SESSION* sess = &ssl->session;
                 word32           milli;
 

src/tls13.c

@@ -3173,6 +3173,9 @@ static int DoPreSharedKeys(WOLFSSL* ssl, const byte* input, word32 helloSz,
         break;
     }
 
+    if (current == NULL)
+        return 0;
+
     /* Hash the rest of the ClientHello. */
     ret = HashInputRaw(ssl, input + helloSz - bindersLen, bindersLen);
     if (ret != 0)