[sailfish-browser] Don't include QMozWindow in the Qt object tree.
[sailfish-browser] Don't include QMozWindow in the Qt object tree.

We want to destroy the object as soon as we null the pointer to it. The
destruction needs to happen when EmbedLiteApp instance is still active
and can receive requests from the user. Without this the final call to
QMozWindow destructor happens after EmbedLite app enters STOPPED state.

sailfishos/sailfish-browser,sailfishos/sailfish-browser,sailfishos/sailfish-browser,sailfishos/sailfish-browser,sailfishos/sailfish-browser