Remove unused variable.

Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4367)

fuzz/server.c

@@ -507,7 +507,9 @@ int FuzzerTestOneInput(const uint8_t *buf, size_t len)
     SSL *server;
     BIO *in;
     BIO *out;
+#if !defined(OPENSSL_NO_EC) || !defined(OPENSSL_NO_DSA)
     BIO *bio_buf;
+#endif
     SSL_CTX *ctx;
     int ret;
     RSA *privkey;