Importer: Local permissions should be set before update_constrains

[ericof]

A pattern I use, to avoid having all content types available everywhere in a site, is to set no roles for the add permission on rolemap.xml and then set the permission only in the folderish location I want the content type to be added,
Also, I usually set constrains in the folderish location, to restrict only a subset of the content types to be added.

Currently, this pattern does not work because constrains cannot be properly set because the permission is not already in place.