Fixes XdgDirs::dataHome() regression
Fixes XdgDirs::dataHome() regression

Internally we were using DataLocation instead of GenericDataLocation.
Closes lxde/lxqt#578.

libqtxdg/libqtxdg,lxde/libqtxdg,lxde/libqtxdg,DrTobe/libqtxdg,luis-pereira/libqtxdg,libqtxdg/libqtxdg,DrTobe/libqtxdg,DrTobe/libqtxdg,luis-pereira/libqtxdg