Dead code identified by Coverty

** CID 1399645:  Control flow issues  (DEADCODE)
/qt-creator/src/plugins/fakevim/fakevimplugin.cpp: 1637 in FakeVim::Internal::FakeVimPluginPrivate::fold(FakeVim::Internal::FakeVimHandler *, int, bool)()


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*** CID 1399645:  Control flow issues  (DEADCODE)
/qt-creator/src/plugins/fakevim/fakevimplugin.cpp: 1637 in FakeVim::Internal::FakeVimPluginPrivate::fold(FakeVim::Internal::FakeVimHandler *, int, bool)()
1631                     // recursively open fold
1632                     while (depth < 0 && block.isValid()
1633                         && TextDocumentLayout::foldingIndent(block) >= indent) {
1634                         if (TextDocumentLayout::canFold(block)) {
1635                             TextDocumentLayout::doFoldOrUnfold(block, true);
1636                             if (depth > 0)
>>>    CID 1399645:  Control flow issues  (DEADCODE)
>>>    Execution cannot reach this statement: "--depth;".
1637                                 --depth;
1638                         }
1639                         block = block.next();
1640                     }
1641                 } else {
1642                     if (TextDocumentLayout::canFold(block)) {

** CID 1399644:  Error handling issues  (CHECKED_RETURN)
/qt-creator/src/plugins/fakevim/fakevimplugin.cpp: 1970 in FakeVim::Internal::FakeVimPluginPrivate::handleExCommand(FakeVim::Internal::FakeVimHandler *, bool *, const FakeVim::Internal::ExCommand &)()


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*** CID 1399644:  Error handling issues  (CHECKED_RETURN)
/qt-creator/src/plugins/fakevim/fakevimplugin.cpp: 1970 in FakeVim::Internal::FakeVimPluginPrivate::handleExCommand(FakeVim::Internal::FakeVimHandler *, bool *, const FakeVim::Internal::ExCommand &)()
1964             const QString fileName = handler->currentFileName();
1965             if (editor && editor->document()->filePath().toString() == fileName) {
1966                 triggerAction(Core::Constants::SAVE);
1967                 saved = !editor->document()->isModified();
1968                 if (saved) {
1969                     QFile file3(fileName);
>>>    CID 1399644:  Error handling issues  (CHECKED_RETURN)
>>>    Calling "open" without checking return value (as is done elsewhere 129 out of 147 times).
1970                     file3.open(QIODevice::ReadOnly);
1971                     const QByteArray ba = file3.readAll();
1972                     handler->showMessage(MessageInfo, Tr::tr("\"%1\" %2 %3L, %4C written")
1973                         .arg(fileName).arg(' ').arg(ba.count('\n')).arg(ba.size()));
1974                     if (cmd.cmd == "wq")
1975                         delayedQuitRequested(cmd.hasBang, m_editorToHandler.key(handler));