In a512e210ac5b032c5fc2edf1ddf72e5a414485fda512e21 quitOnLastWindowClosed
was changed to be implemented in terms of quitLockEnabled, but without
any documentation to that end.
Although the two features are similar (automatic quit under certain
conditions), and interact, it doesn't make sense to overlap them until
we actually expose them as a single property (automaticQuit e.g.)
The logic for determining whether we can can quit automatically has
been refactored to take both properties into account, on both a Core
and Gui level. The call sites still need to check the individual
properties to determine whether to activate automatic quit for
that particular code path.
Change-Id: I38c3e8cb30db373ea73dd45f150e5048c0db2f4d
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>