session management never works.

[xylosper@mbp13 gui]$ pwd
/home/xylosper/downloads/qt-everywhere-opensource-src-5.0.1/qtbase/src/gui
[xylosper@mbp13 gui]$ grep -r commitDataRequest *
kernel/qguiapplication.h:    void commitDataRequest(QSessionManager &sessionManager);
kernel/qguiapplication.cpp:                See isSessionRestored(), sessionId() and commitDataRequest() and
kernel/qguiapplication.cpp:            commitDataRequest(),
kernel/qguiapplication.cpp:    \fn void QGuiApplication::commitDataRequest(QSessionManager &manager)
kernel/qguiapplication.cpp:    \sa isSessionRestored(), sessionId(), commitDataRequest(), {Session Management}
kernel/qguiapplication.cpp:    \sa sessionId(), commitDataRequest(), saveStateRequest()
kernel/qguiapplication.cpp:    This is true when commitDataRequest() and saveStateRequest() are emitted,
kernel/qguiapplication.cpp:    \sa sessionId(), commitDataRequest(), saveStateRequest()
kernel/qguiapplication.cpp:    \sa isSessionRestored(), sessionKey(), commitDataRequest(), saveStateRequest()
kernel/qguiapplication.cpp:    \sa isSessionRestored(), sessionId(), commitDataRequest(), saveStateRequest()
kernel/qguiapplication.cpp:    emit q->commitDataRequest(manager);

[xylosper@mbp13 gui]$ grep -r commitData\( *
doc/snippets/code/src_gui_kernel_qapplication.cpp:void MyApplication::commitData(QSessionManager& manager)
kernel/qguiapplication_p.h:    void commitData(QSessionManager& sm);
kernel/qsessionmanager.cpp:    virtual functions QApplication::commitData() and QApplication::saveState().
kernel/qsessionmanager.cpp:    commitData() function does this if some top-level window rejected its
kernel/qsessionmanager.cpp:    The session key changes with every call of commitData() or saveState().
kernel/qsessionmanager.cpp:    Here's an example of how an application's QApplication::commitData() might
kernel/qsessionmanager.cpp:    \sa QApplication::commitData(), release(), cancel()
kernel/qsessionmanager.cpp:    application may then return immediately from the QApplication::commitData()
kernel/qguiapplication.cpp:void QGuiApplicationPrivate::commitData(QSessionManager& manager)