Fixed Valentina crash. Used way to avoid Qt's bug QTBUG-61213.

(grafted from 07ea72e1470337f51b895efaae01deecfbac6aaf)

--HG--
branch : develop

ChangeLog.txt

@@ -36,6 +36,7 @@
 - Tool Seam allowance's bounding box should not include passmarks.
 - Fix grainline position on layout.
 - [#719] Valentina crashes when unite pieces.
+- Fixed Valentina crash. Used way to avoid Qt's bug QTBUG-61213.
 
 # Version 0.5.0 May 9, 2017
 - [#581] User can now filter input lists by keyword in function wizard.

src/libs/vwidgets/vwidgetpopup.cpp

@@ -92,7 +92,7 @@ void VWidgetPopup::PopupMessage(QWidget *w, const QString &msg)
 {
     SCASSERT(w != nullptr)
 
-    VWidgetPopup *popup = new VWidgetPopup();
+    VWidgetPopup *popup = new VWidgetPopup(w);
     QLabel *label = new QLabel(msg);
     QFont f = label->font();
     f.setBold(true);