esp_http_client: fix memory leak in esp_http_client_set_username/password

Fix memory in case username/password was set before calling
esp_http_client_set_username/password.

Closes https://github.com/espressif/esp-idf/issues/4444
Fixes: 9fd16c6a5ff7 ("fixes : set_url discards username and password")
Signed-off-by: Axel Lin <axel.lin@gmail.com>

components/esp_http_client/esp_http_client.c

@@ -300,12 +300,10 @@ esp_err_t esp_http_client_set_username(esp_http_client_handle_t client, const ch
         ESP_LOGE(TAG, "client must not be NULL");
         return ESP_ERR_INVALID_ARG;
     }
-    if (username == NULL && client->connection_info.username != NULL) {
+    if (client->connection_info.username != NULL) {
         free(client->connection_info.username);
-        client->connection_info.username = NULL;
-    } else if (username != NULL) {
-        client->connection_info.username = strdup(username);
     }
+    client->connection_info.username = username ? strdup(username) : NULL;
     return ESP_OK;
 }
 
@@ -325,13 +323,11 @@ esp_err_t esp_http_client_set_password(esp_http_client_handle_t client, char *pa
         ESP_LOGE(TAG, "client must not be NULL");
         return ESP_ERR_INVALID_ARG;
     }
-    if (password == NULL && client->connection_info.password != NULL) {
+    if (client->connection_info.password != NULL) {
         memset(client->connection_info.password, 0, strlen(client->connection_info.password));
         free(client->connection_info.password);
-        client->connection_info.password = NULL;
-    } else if (password != NULL) {
-        client->connection_info.password = strdup(password);
     }
+    client->connection_info.password = password ? strdup(password) : NULL;
     return ESP_OK;
 }