[BISERVER-12093] - Cannot delete invalid Data Source

The check for mondrian schema file was commented because we can't suppose that it is a valid xml file (changed lines 586-594).
Also was changed processing mondrian catalogs in method "loadCatalogsIntoCache". We load into cache all catalogs which were uploaded into repository.
This is related PR for https://github.com/pentaho/data-access/pull/582

@lucboudreau Luc, please review this commit too.