C++: FP in cpp/resource-not-released-in-destructor

[s0]

As reported here: https://discuss.lgtm.com/t/false-positive-resource-not-released-in-destructor/1938

https://lgtm.com/projects/g/KDE/kphotoalbum/snapshot/fe21e4ad620bf50c37ed9b9ec38a1941eb9b5fac/files/Exif/Database.cpp#x7903eb9a495cd189:1 2

In this case, the boolean member variable m_isOpen is mistaken for the resource that is acquired, when in fact the QSqlDatabase m_db holds the resource (and is correctly released in the dtor).

[geoffw0]

Fix here: #1162