Backport SVN commit 912210 by pino:

Correctly set the custom paper size of the dummy printer.
CCBUG: 178087

svn path=/branches/KDE/4.2/kdegraphics/okular/; revision=912214

generators/poppler/generator_pdf.cpp

@@ -848,6 +848,7 @@ bool PDFGenerator::print( QPrinter& printer )
     dummy.setFullPage( true );
     dummy.setOrientation( printer.orientation() );
     dummy.setPageSize( printer.pageSize() );
+    dummy.setPaperSize( printer.paperSize( QPrinter::Millimeter ), QPrinter::Millimeter );
     int width = dummy.width();
     int height = dummy.height();