use QString::clear() to clear a QString instead of assigning QString().

svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=870305

delegate.cpp

@@ -246,7 +246,7 @@ void Delegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
     }
 
     if (subTitleText == titleText) {
-        subTitleText = QString();
+        subTitleText.clear();
     }
 
     QFont subTitleFont = d->fontForSubTitle(option.font);

svg.cpp

@@ -87,7 +87,8 @@ class SvgPrivate
             }
 
             themed = !QDir::isAbsolutePath(imagePath);
-            path = themePath = QString();
+            path.clear();
+            themePath.clear();
 
             if (themed) {
                 themePath = imagePath;

theme.cpp

@@ -457,7 +457,7 @@ void Theme::setUseGlobalSettings(bool useGlobal)
 
     d->useGlobal = useGlobal;
     d->cfg = KConfigGroup();
-    d->themeName = QString();
+    d->themeName.clear();
     settingsChanged();
 }