fix: correct status code separator logic in JSON display

Author: wpjunior

src/ngx_http_vhost_traffic_status_display_json.c

@@ -106,16 +106,18 @@ ngx_http_vhost_traffic_status_display_set_server_node(
  buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_SERVER_STATUS_CODE_START);
 
  ngx_uint_t *status_codes = (ngx_uint_t *) ctx->measure_status_codes->elts;
+ ngx_uint_t inserted = 0;
  for (ngx_uint_t i = 0; i < ctx->measure_status_codes->nelts; i++) {
  if (vtsn->stat_status_code_counter[i] == 0 && ctx->measure_all_status_codes) {
  continue;
  }
  status_code = &status_codes[i];
- if (i > 0) {
+ if (inserted > 0) {
  buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_SERVER_STATUS_SEPARATOR);
  }
  buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_SERVER_STATUS_CODE,
  *status_code, vtsn->stat_status_code_counter[i]);
+ inserted++;
  }
 
  buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_SERVER_STATUS_CODE_END);