[EPubGenerator] Reduce nesting level in loop

Summary:
The loop body is skipped when `epub_it_get_curr(it)` is invalid.
Make it more obvious there is no more code executed in this case.

Test Plan: no functional changes

Reviewers: #okular, ngraham

Reviewed By: ngraham

Subscribers: okular-devel

Tags: #okular

Differential Revision: https://phabricator.kde.org/D20946

generators/epub/converter.cpp

@@ -203,10 +203,13 @@ QTextDocument* Converter::convert( const QString &fileName )
   QVector<Okular::SoundAction *> soundActions;
   const QSize videoSize(320, 240);
   do{
-    movieAnnots.clear();
-    soundActions.clear();
+      if(!epub_it_get_curr(it)) {
+        continue;
+      }
+
+      movieAnnots.clear();
+      soundActions.clear();
 
-    if(epub_it_get_curr(it)) {
       const QString link = QString::fromUtf8(epub_it_get_curr_url(it));
       mTextDocument->setCurrentSubDocument(link);
       QString htmlContent = QString::fromUtf8(epub_it_get_curr(it));
@@ -354,7 +357,7 @@ QTextDocument* Converter::convert( const QString &fileName )
 
       while(mTextDocument->pageCount() == page)
         _cursor->insertText(QStringLiteral("\n"));
-    }
+
   } while (epub_it_get_next(it));
 
   epub_free_iterator(it);