Fix incorrect example for evil-escape-key-sequence

When I followed the example in the documentation, `describe-variable` reflected the updated value ("jj") but spacemacs ignored it and continued to use the default value ("fd").

`evil-escape.el` mentions:

```elisp
;; The key sequence can be customized with the variable
;; `evil-escape-key-sequence'
;; It must be set before requiring evil-escape.
```

So I tried moving the `setq` to `/init` instead of `/config`. That worked.