protect from closing on changing sessions

--disable quiting the app when there are no windows
shown. There are cases that between states some
windows may not exist. E.g. when changing sessions
and when activating/deactivating screens

app/main.cpp

@@ -66,6 +66,8 @@ int main(int argc, char **argv)
     QApplication app(argc, argv);
     KLocalizedString::setApplicationDomain("latte-dock");
     app.setWindowIcon(QIcon::fromTheme(QStringLiteral("latte-dock")));
+    //protect from closing app when changing to "alternative session" and back
+    app.setQuitOnLastWindowClosed(false);
 
     configureAboutData();
 
@@ -86,8 +88,10 @@ int main(int argc, char **argv)
     QLockFile lockFile {QDir::tempPath() + "/latte-dock.lock"};
 
     int timeout {100};
+
     if (parser.isSet(QStringLiteral("replace")) || parser.isSet(QStringLiteral("import"))) {
-        qint64 pid{-1};
+        qint64 pid{ -1};
+
         if (lockFile.getLockInfo(&pid, nullptr, nullptr)) {
             kill(static_cast<pid_t>(pid), SIGINT);
             timeout = 3000;