AgentBase::setOnline fix nullptr dereference
To reproduce trigger cleanup from akonadiconsole
sample trace:
#4 0x00007f03e3ae174a in QSettings::setValue(QString const&, QVariant const&) () at /usr/lib/libQt5Core.so.5
#5 0x00007f03e55446bf in Akonadi::AgentBase::setOnline(bool) () at /usr/lib/libKF5AkonadiAgentBase.so.5
#6 0x00007f03e5570033 in () at /usr/lib/libKF5AkonadiAgentBase.so.5
#7 0x00007f03e3e27066 in () at /usr/lib/libQt5DBus.so.5
...
Edited by nib 952051