Setup plone.app.event’s indices in the catalog.
Doing it here instead of in profiles/default/catalog.xml means we
do not need to reindex those indexes after every reinstall.
- See these discussions for more info about index clearing with catalog.xml:
- http://plone.293351.n2.nabble.com/How-to-import-catalog-xml-without-
emptying-the-indexes-td2302709.html
https://mail.zope.org/pipermail/zope-cmf/2007-March/025664.html