Fix a crash in case of setting invalid point size
Fix a crash in case of setting invalid point size

Asserts are replaced with warnings and the call is ignored.

Task-number: 252414, 252416, 252502
Reviewed-by: Simon Hausmann <a975102812d593b3191088e3d0aeaeb6f11dbcf5@nokia.com>

RLovelett/qt,KDE/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,RLovelett/qt,RLovelett/qt,RLovelett/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,KDE/qt,radekp/qt,pruiz/wkhtmltopdf-qt,RLovelett/qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,radekp/qt,radekp/qt,igor-sfdc/qt-wk,radekp/qt,radekp/qt,KDE/qt,KDE/qt,pruiz/wkhtmltopdf-qt,KDE/qt,radekp/qt,RLovelett/qt,RLovelett/qt,igor-sfdc/qt-wk,RLovelett/qt,radekp/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,KDE/qt,KDE/qt,pruiz/wkhtmltopdf-qt,radekp/qt,RLovelett/qt,igor-sfdc/qt-wk,radekp/qt,RLovelett/qt,igor-sfdc/qt-wk,radekp/qt,igor-sfdc/qt-wk,KDE/qt,RLovelett/qt