config_format: cf_yaml: Address review comments

Signed-off-by: Hiroshi Hatake <hiroshi@chronosphere.io>

Author: cosmo0920

src/config_format/flb_cf_yaml.c

@@ -1950,6 +1950,19 @@ static int consume_event(struct flb_cf *conf, struct local_ctx *ctx,
                     return YAML_FAILURE;
                 }
             }
+            else if (state->section == SECTION_METADATA) {
+                variant = state_variant_parse_scalar(event);
+                if (variant == NULL) {
+                    flb_error("unable to allocate memory for variant");
+                    return YAML_FAILURE;
+                }
+
+                if (cfl_kvlist_insert(state->cf_section->properties, state->key, variant) < 0) {
+                    cfl_variant_destroy(variant);
+                    flb_error("unable to insert variant");
+                    return YAML_FAILURE;
+                }
+            }
             else {
 
                 /* register key/value pair as a property */
@@ -2418,6 +2431,7 @@ static int consume_event(struct flb_cf *conf, struct local_ctx *ctx,
                 }
 
                 if (cfl_kvlist_insert(state->cf_section->properties, state->key, variant) < 0) {
+                    cfl_variant_destroy(variant);
                     flb_error("unable to insert variant");
                     return YAML_FAILURE;
                 }