EZP-21206 - Disable key normalization for ezpublish.system's children

This PR fixes an issue with siteaccess matching, where siteaccesses with dashes, i.e `por-PT` appear to match correctly, but its prioritized language list is ignored, and falls-back to the default configurations.

Further details available here:
**JIRA**: https://jira.ez.no/browse/EZP-21206