Fix Krazy warnings about QString::null/clear().

Change-Id: I11faa5af0c186a9126c4af6f86e56250030d6cd9
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>
Reviewed-by: Laszlo Papp <lpapp@kde.org>
Reviewed-by: David Schulz <david.schulz@digia.com>
Reviewed-by: Jarek Kobus <jaroslaw.kobus@digia.com>

src/libs/qmljs/qmljscompletioncontextfinder.cpp

@@ -308,7 +308,7 @@ void CompletionContextFinder::checkImport()
         if (m_libVersion.isNull())
             m_libVersion = QLatin1String("");
     } else {
-        m_libVersion = QString();
+        m_libVersion.clear();
     }
 }
 

src/plugins/diffeditor/differ.cpp

@@ -294,8 +294,8 @@ QList<Diff> Differ::diffNonCharMode(const QString text1, const QString text2)
                 // Rediff here on char basis
                 newDiffList += preprocess1AndDiff(lastDelete, lastInsert);
 
-                lastDelete = QString();
+                lastDelete.clear();
-                lastInsert = QString();
+                lastInsert.clear();
             }
             newDiffList.append(diffItem);
         }
@@ -406,8 +406,8 @@ QList<Diff> Differ::merge(const QList<Diff> &diffList)
                     newDiffList.append(Diff(Diff::Insert, lastInsert));
                 if (diff.text.count())
                     newDiffList.append(diff);
-                lastDelete = QString();
+                lastDelete.clear();
-                lastInsert = QString();
+                lastInsert.clear();
             } else { // join with last equal diff
                 if (newDiffList.count()
                         && newDiffList.last().command == Diff::Equal) {

src/plugins/madde/maemodeviceconfigwizard.cpp

@@ -561,7 +561,7 @@ IDevice::Ptr MaemoDeviceConfigWizard::device()
     sshParams.port = d->wizardData.sshPort;
     if (d->wizardData.machineType == IDevice::Emulator) {
         sshParams.authenticationType = QSsh::SshConnectionParameters::AuthenticationByPassword;
-        sshParams.password = QString();
+        sshParams.password.clear();
         sshParams.timeout = 30;
         freePortsSpec = QLatin1String("13219,14168");
         doTest = false;

src/plugins/qmldesigner/designercore/metainfo/metainforeader.cpp

@@ -143,7 +143,7 @@ MetaInfoReader::ParserSate MetaInfoReader::readDocument(const QString &name)
 {
     if (name == QLatin1String(rootElementName)) {
         m_currentClassName.clear();
-        m_currentIcon = QString();
+        m_currentIcon.clear();
         return ParsingMetaInfo;
     } else {
         addErrorInvalidType(name);
@@ -155,7 +155,7 @@ MetaInfoReader::ParserSate MetaInfoReader::readMetaInfoRootElement(const QString
 {
     if (name == QLatin1String(typeElementName)) {
         m_currentClassName.clear();
-        m_currentIcon = QString();
+        m_currentIcon.clear();
         return ParsingType;
     } else {
         addErrorInvalidType(name);
@@ -183,7 +183,7 @@ MetaInfoReader::ParserSate MetaInfoReader::readItemLibraryEntryElement(const QSt
         return ParsingQmlSource;
     } else if (name == PropertyElementName) {
         m_currentPropertyName = PropertyName();
-        m_currentPropertyType = QString();
+        m_currentPropertyType.clear();
         m_currentPropertyValue = QVariant();
         return ParsingProperty;
     } else {

src/plugins/qt4projectmanager/profilehoverhandler.cpp

@@ -69,7 +69,7 @@ bool ProFileHoverHandler::acceptEditor(IEditor *editor)
 
 void ProFileHoverHandler::identifyMatch(TextEditor::ITextEditor *editor, int pos)
 {
-    m_docFragment = QString();
+    m_docFragment.clear();
     m_manualKind = UnknownManual;
     if (ProFileEditorWidget *proFileEditor = qobject_cast<ProFileEditorWidget *>(editor->widget())) {
         if (!proFileEditor->extraSelectionTooltip(pos).isEmpty()) {

src/plugins/texteditor/codeassist/defaultassistinterface.cpp

@@ -74,7 +74,7 @@ void DefaultAssistInterface::prepareForAsyncUse()
 void DefaultAssistInterface::recreateTextDocument()
 {
     m_textDocument = new QTextDocument(m_text);
-    m_text = QString();
+    m_text.clear();
 }
 
 AssistReason DefaultAssistInterface::reason() const

src/plugins/texteditor/codestylepool.cpp

@@ -245,7 +245,7 @@ ICodeStylePreferences *CodeStylePool::loadCodeStyle(const Utils::FileName &fileN
             codeStyle = d->m_factory->createCodeStyle();
             codeStyle->setId(id);
             codeStyle->setDisplayName(displayName);
-            codeStyle->fromMap(QString::null, map);
+            codeStyle->fromMap(QString(), map);
 
             addCodeStyle(codeStyle);
         }
@@ -284,7 +284,7 @@ void CodeStylePool::saveCodeStyle(ICodeStylePreferences *codeStyle) const
 void CodeStylePool::exportCodeStyle(const Utils::FileName &fileName, ICodeStylePreferences *codeStyle) const
 {
     QVariantMap map;
-    codeStyle->toMap(QString::null, &map);
+    codeStyle->toMap(QString(), &map);
 
     QVariantMap tmp;
     tmp.insert(QLatin1String(displayNameKey), codeStyle->displayName());

src/plugins/texteditor/codestyleselectorwidget.cpp

@@ -343,7 +343,7 @@ void CodeStyleSelectorWidget::slotRemoveClicked()
 void CodeStyleSelectorWidget::slotImportClicked()
 {
     const Utils::FileName fileName =
-            Utils::FileName::fromString(QFileDialog::getOpenFileName(this, tr("Import Code Style"), QString::null,
+            Utils::FileName::fromString(QFileDialog::getOpenFileName(this, tr("Import Code Style"), QString(),
                                                                      tr("Code styles (*.xml);;All files (*)")));
     if (!fileName.isEmpty()) {
         CodeStylePool *codeStylePool = m_codeStyle->delegatingPool();