Use correct variable in test diagnostic

create_ssl_connection() prints out the results if SSL_accept() and/or
SSL_connect() fail, but was reusing the client return value when printing
about SSL_accept() failures.
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2279)

test/ssltestlib.c

@@ -669,7 +669,7 @@ int create_ssl_connection(SSL *serverssl, SSL *clientssl)
         }
 
         if (!servererr && rets <= 0 && err != SSL_ERROR_WANT_READ) {
-            printf("SSL_accept() failed %d, %d\n", retc, err);
+            printf("SSL_accept() failed %d, %d\n", rets, err);
             servererr = 1;
         }
         if (clienterr && servererr)