Do not use QAbstractItemModel::reset().

Change-Id: Ie49bdf576a6d3543aef6df133b27c8827775c935
Rationale:
    a) It is conceptually cleaner to do the changes to the model
       in between calls to beginResetModel() and endResetModel,
       respectively.
    b) The function is deprecated in Qt 5, for exactly that reason.
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/texteditor/fontsettingspage.cpp

@@ -101,8 +101,9 @@ public:
 
     void setColorSchemes(const QList<ColorSchemeEntry> &colorSchemes)
     {
+        beginResetModel();
         m_colorSchemes = colorSchemes;
-        reset();
+        endResetModel();
     }
 
     const ColorSchemeEntry &colorSchemeAt(int index) const