Fix initial window orientation with Qt on MeeGo 1.2 Harmattan

Fix initial window orientation with Qt on MeeGo 1.2 Harmattan

The window orientation changes are handled through a generic QPA plugin and
sends an initial window orientation change event on startup for the initial
orientation and subsequent updates when the device orientation changes.

Unfortunately the plugin was never loaded after the introduction of the new
plugin loading mechanism, because the factory key ("MeeGoIntegration") was
not provided to the plugin registry.

Change-Id: Ib7324561993abfbac1dccb0839aab0a8e870d231
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>
Reviewed-by: Laszlo Papp <lpapp@kde.org>