Fix detection of Oxygen style

Change-Id: I2a28335285869ce477d2c71532ccb44046a0cfa7
Reviewed-by: Daniel Teske <daniel.teske@nokia.com>

src/plugins/coreplugin/manhattanstyle.cpp

@@ -271,7 +271,7 @@ void ManhattanStyle::polish(QWidget *widget)
     QProxyStyle::polish(widget);
 
     // OxygenStyle forces a rounded widget mask on toolbars and dock widgets
-    if (baseStyle()->inherits("OxygenStyle")) {
+    if (baseStyle()->inherits("OxygenStyle") || baseStyle()->inherits("Oxygen::Style")) {
         if (qobject_cast<QToolBar*>(widget) || qobject_cast<QDockWidget*>(widget)) {
             widget->removeEventFilter(baseStyle());
             widget->setContentsMargins(0, 0, 0, 0);