Description of problem:
KDE plasma of Fedora 25 is affected of the problem cited in KDE Bugzilla #370516. This means that each attempt of loading KDE Plasma ends in a crash, since a certain Qt connection is a certain Qt:UniqueConnection is registered multiple times.

Version-Release number of selected component (if applicable):
plasma-desktop-5.8.1-1.fc25.x86_64
qt5-qtbase.x86_64 5.7.0-3.fc25

How reproducible:
Always if more than one activity has been set up in an earlier KDE Plasma release.

Actual results:
Crash.

Head of the stacktrace:
Thread 1 "plasmashell" received signal SIGSEGV, Segmentation fault.
0x00007fff326dd300 in ?? () from /usr/lib/qt/qml/org/kde/plasma/private/pager/libpagerplugin.so
(gdb) bt
#0  0x00007fff326dd300 in ?? () from /usr/lib/qt/qml/org/kde/plasma/private/pager/libpagerplugin.so
#1  0x00007ffff1ee8cb4 in QObjectPrivate::connectImpl(QObject const*, int, QObject const*, void**, QtPrivate::QSlotObjectBase*, Qt::ConnectionType, int const*, QMetaObject const*) () from /usr/lib/libQt5Core.so.5
#2  0x00007ffff1ee8f12 in QObject::connectImpl(QObject const*, void**, QObject const*, void**, QtPrivate::QSlotObjectBase*, Qt::ConnectionType, int const*, QMetaObject const*) () from /usr/lib/libQt5Core.so.5
#3  0x00007fff326da256 in ?? () from /usr/lib/qt/qml/org/kde/plasma/private/pager/libpagerplugin.so
#4  0x00007fff326dafef in ?? () from /usr/lib/qt/qml/org/kde/plasma/private/pager/libpagerplugin.so
#5  0x00007ffff50336bc in ?? () from /usr/lib/libQt5Qml.so.5
#6  0x00007ffff4fc0cf2 in ?? () from /usr/lib/libQt5Qml.so.5
#7  0x00007ffff4fc18f4 in QQmlIncubationController::incubateFor(int) () from /usr/lib/libQt5Qml.so.5
#8  0x00007ffff60cef6c in ?? () from /usr/lib/libKF5Declarative.so.5
...

Expected results:
None

Additional info: