Error logged when editing SNV

[boubaker]

Steps to reproduce

Steps to reproduce the behavior:

1. Go to a page containing an existing SNV
2. Click on Edit to edit the SNV content
3. Save modified SNV content
4. See error in logs

Current behaviour

Error logged in Server console:

An error occurred while retrieving news with id 50 [i.m.news.service.impl.NewsServiceImpl<http-nio-0.0.0.0-8080-exec-1>] 
java.lang.NullPointerException: Cannot invoke "org.exoplatform.wiki.model.PageVersion.getAuthor()" because "pageVersion" is null
	at io.meeds.news.service.impl.NewsServiceImpl.buildArticle(NewsServiceImpl.java:1989)
	at io.meeds.news.service.impl.NewsServiceImpl.getNewsArticleByIdAndLang(NewsServiceImpl.java:547)
	at io.meeds.news.service.impl.NewsServiceImpl.getNewsArticleById(NewsServiceImpl.java:540)
	at io.meeds.news.listener.ExternalArticlePageListener.onEvent(ExternalArticlePageListener.java:74)
	at org.exoplatform.services.listener.ListenerService.broadcast(ListenerService.java:168)
	at org.exoplatform.wiki.utils.Utils.broadcast(Utils.java:690)
	at org.exoplatform.wiki.service.impl.NoteServiceImpl.updateNote(NoteServiceImpl.java:387)
	at org.exoplatform.wiki.service.impl.NoteServiceImpl.updateNote(NoteServiceImpl.java:399)
	at io.meeds.notes.service.NotePageViewService.saveNotePage(NotePageViewService.java:201)
	at io.meeds.notes.service.NotePageViewService.saveNotePage(NotePageViewService.java:171)
	at io.meeds.notes.rest.NotePageViewRest.saveNotePage(NotePageViewRest.java:160)