i18n-extract should always try to load .i18nrc from ./

This is not the case now, which makes configuration hard in some scenarios.

For example, I added the following extract command to `client/locales/package.json`

```
i18n-extract \"../guide/src/**/*.js\" messages.pot && i18n-merge messages.pot *.po
```
Now, signavio-i18n expects `.i18nrc` to be in `client/guide`.