Security: fix redis-cli buffer overflow.

Thanks to Fakhri Zulkifli for reporting it.

The fix switched to dynamic allocation, copying the final prompt in the
static buffer only at the end.
static void statMode(void) {
    redisReply *reply;
    long aux, requests = 0;
    int i = 0;

    while(1) {
        char buf[64];
        int j;

        reply = reconnectingRedisCommand(context,"INFO");
        if (reply->type == REDIS_REPLY_ERROR) {
            printf("ERROR: %s\n", reply->str);
            exit(1);
        }

        if ((i++ % 20) == 0) {
            printf(
"------- data ------ --------------------- load -------------------- - child -\n"
"keys       mem      clients blocked requests            connections          \n");
        }

        /* Keys */
        aux = 0;
        for (j = 0; j < 20; j++) {
            long k;

            sprintf(buf,"db%d:keys",j);
            k = getLongInfoField(reply->str,buf);
            if (k == LONG_MIN) continue;
            aux += k;
        }
        sprintf(buf,"%ld",aux);
        printf("%-11s",buf);

        /* Used memory */
        aux = getLongInfoField(reply->str,"used_memory");
        bytesToHuman(buf,aux);
        printf("%-8s",buf);

        /* Clients */
        aux = getLongInfoField(reply->str,"connected_clients");
        sprintf(buf,"%ld",aux);
        printf(" %-8s",buf);

        /* Blocked (BLPOPPING) Clients */
        aux = getLongInfoField(reply->str,"blocked_clients");
        sprintf(buf,"%ld",aux);
        printf("%-8s",buf);

        /* Requests */
        aux = getLongInfoField(reply->str,"total_commands_processed");
        sprintf(buf,"%ld (+%ld)",aux,requests == 0 ? 0 : aux-requests);
        printf("%-19s",buf);
        requests = aux;

        /* Connections */
        aux = getLongInfoField(reply->str,"total_connections_received");
        sprintf(buf,"%ld",aux);
        printf(" %-12s",buf);

        /* Children */
        aux = getLongInfoField(reply->str,"bgsave_in_progress");
        aux |= getLongInfoField(reply->str,"aof_rewrite_in_progress") << 1;
        aux |= getLongInfoField(reply->str,"loading") << 2;
        switch(aux) {
        case 0: break;
        case 1:
            printf("SAVE");
            break;
        case 2:
            printf("AOF");
            break;
        case 3:
            printf("SAVE+AOF");
            break;
        case 4:
            printf("LOAD");
            break;
        }

        printf("\n");
        freeReplyObject(reply);
        usleep(config.interval);
    }
}

static void statMode(void) {
    redisReply *reply;
    long aux, requests = 0;
    int i = 0;

    while(1) {
        char buf[64];
        int j;

        reply = reconnectingRedisCommand(context,"INFO");
        if (reply->type == REDIS_REPLY_ERROR) {
            printf("ERROR: %s\n", reply->str);
            exit(1);
        }

        if ((i++ % 20) == 0) {
            printf(
"------- data ------ --------------------- load -------------------- - child -\n"
"keys       mem      clients blocked requests            connections          \n");
        }

        /* Keys */
        aux = 0;
        for (j = 0; j < 20; j++) {
            long k;

            sprintf(buf,"db%d:keys",j);
            k = getLongInfoField(reply->str,buf);
            if (k == LONG_MIN) continue;
            aux += k;
        }
        sprintf(buf,"%ld",aux);
        printf("%-11s",buf);

        /* Used memory */
        aux = getLongInfoField(reply->str,"used_memory");
        bytesToHuman(buf,aux);
        printf("%-8s",buf);

        /* Clients */
        aux = getLongInfoField(reply->str,"connected_clients");
        sprintf(buf,"%ld",aux);
        printf(" %-8s",buf);

        /* Blocked (BLPOPPING) Clients */
        aux = getLongInfoField(reply->str,"blocked_clients");
        sprintf(buf,"%ld",aux);
        printf("%-8s",buf);

        /* Requests */
        aux = getLongInfoField(reply->str,"total_commands_processed");
        sprintf(buf,"%ld (+%ld)",aux,requests == 0 ? 0 : aux-requests);
        printf("%-19s",buf);
        requests = aux;

        /* Connections */
        aux = getLongInfoField(reply->str,"total_connections_received");
        sprintf(buf,"%ld",aux);
        printf(" %-12s",buf);

        /* Children */
        aux = getLongInfoField(reply->str,"bgsave_in_progress");
        aux |= getLongInfoField(reply->str,"aof_rewrite_in_progress") << 1;
        aux |= getLongInfoField(reply->str,"loading") << 2;
        switch(aux) {
        case 0: break;
        case 1:
            printf("SAVE");
            break;
        case 2:
            printf("AOF");
            break;
        case 3:
            printf("SAVE+AOF");
            break;
        case 4:
            printf("LOAD");
            break;
        }

        printf("\n");
        freeReplyObject(reply);
        usleep(config.interval);
    }
}
