activity_builder field in XWSApps.Blog, Files, Stream, Photos not configured correctly

Upon implementing my own activitystream event type for the Blog application, I found that BlogApplicationActivityBuilder was not being called when it should have been. Instead, ApplicationDefaultActivityBuilder was being called. It turns out that the activity_builder field of the XWiki.XWSApplicationClass object in the XWSApp.BlogApp application document had been entered incorrectly.

Before I updated it, it was: com.xpn.xwiki.plugin.workspacesmanager.activities.BlogApplicationActivityBuilder

After I changed it to: com.xpn.xwiki.plugin.workspacesmanager.apps.activities.builders.BlogApplicationActivityBuilder, the correct class was instantiated.

The same error was found in FilesApp, PhotosApp, and StreamApp.