[BUG]getters and setters

[davisouzaluna]

If I try to create a new client and set a value, it cannot access the memory space. But if it already exists, it can do it. Think about logic

Create New client

• Works:

  
  client_t client;
  client_config_t config;
  size_t buffer_size = 0;
  char *client_id = "test_client_struct";
  
  config.client_id = client_id;
  config.keep_alive = 60;
  config.ip_broker = global_ip_broker;
  config.port_broker = global_port_broker;
  config.default_qos = 0;

create_client(&client, &config, buffer_size);

- Don't work:
```c
    client_t client;
    client_config_t config;
    size_t buffer_size = 0;
    char *client_id = "test_client_struct";

    set_client_id(&client, "test_client_struct");
    printf("debug\n");
    set_keep_alive(&client, 60);
    set_broker_ip(&client, global_ip_broker);
    set_broker_port(&client, global_port_broker);
    set_config(&client, &config);

create_client(&client, &config, buffer_size);

Return error:

Segmentation fault

[davisouzaluna]

commit 138217ac5dbb50d46b1cb021a6a53d122692312e