plone.app.discussion is an official Plone core package,
thus their translations belong to plone.app.locales.
This commit removes the plone.app.discussion domain and changes it for
plone.
This fixes:
https://github.com/plone/plone.app.discussion/issues/66
- zope.app.container is available in both Plone 3 and Plone 4, so the 'not-installed zope.app.container' condition was always false
- zope.lifecycleevent.interfaces does not have an IObjectAddedEvent or IObjectRemovedEvent so even if the condition would have been true, the loading would have failed.
svn path=/plone.app.discussion/trunk/; revision=46367