p5_scrypt.c: fix error check of RAND_bytes() call

Reviewed-by: NKurt Roeckx <kurt@roeckx.be>
(Merged from https://github.com/openssl/openssl/pull/5977)

crypto/asn1/p5_scrypt.c

@@ -82,7 +82,7 @@ X509_ALGOR *PKCS5_pbe2_set_scrypt(const EVP_CIPHER *cipher,
     if (EVP_CIPHER_iv_length(cipher)) {
         if (aiv)
             memcpy(iv, aiv, EVP_CIPHER_iv_length(cipher));
-        else if (RAND_bytes(iv, EVP_CIPHER_iv_length(cipher)) < 0)
+        else if (RAND_bytes(iv, EVP_CIPHER_iv_length(cipher)) <= 0)
             goto err;
     }