Bug Fixes in KDE Base
Add paths to qt plugins (from kstandarddirs) before qapp is created.
Necessary for apps started through d-bus activation, so that the kde widget
style is loaded. The QCoreApp::instance test was "so that qt.conf is read" (db852684)
but the whole idea of 9d7eb8f7 is that this doesn't rely on the qt config files anymore.
(cherry picked from commit 979a19afe93d1e4a5be684c1139b6ab242e6b9b6)