fix: Products.CMFPlone needs the gopip index from plone.app.folder.
So latter has to be initialized before CMFPlones profile is applied (which installs the index to catalog).
At the moment CMFPlone therefore registers the index itself, but plone.app.folder registers it too, which resulted in plone/Products.CMFPlone#313 "GopipIndex registered twice"
In tests the registration does not succedd, because plone.app.folder was never initialized as z2 products.
In order to remove the misleading regisatration from CMFPlone we must take care that the index is available, which is achieved with this change.
Also minor pep8 optimizations in the file touched.