config: fix compilation with FLB_HAVE_STATIC_CONF

Fixes:

```
/src/src/config_format/flb_cf_yaml.c: In function 'state_create':
/src/src/config_format/flb_cf_yaml.c:1906:5: error: 's' undeclared (first use in this function)
     s->file->name = flb_sds_create("***static***");
     ^
```

src/config_format/flb_cf_yaml.c

@@ -1903,8 +1903,8 @@ static struct parser_state *state_create(struct file_state *parent, struct file_
 
 #else
 
-    s->file->name = flb_sds_create("***static***");
-    s->file->path = flb_sds_create("***static***");
+    state->file->name = flb_sds_create("***static***");
+    state->file->path = flb_sds_create("***static***");
 
 #endif