[kiriki] avoid memory leak

Summary:
Set again the parent so it is deleted automatically.
avoid this memory leak:
Indirect leak of 72 byte(s) in 1 object(s) allocated from:
    #0 0x7f39cec39c70 in operator new(unsigned long) (/usr/lib64/libasan.so.4+0xddc70)
    #1 0x4160ed in QList<player>::node_construct(QList<player>::Node*, player const&) /usr/include/qt5/QtCore/qlist.h:435
    #2 0x4160ed in QList<player>::append(player const&) /usr/include/qt5/QtCore/qlist.h:584
    #3 0x4160ed in scores::scores() /g/5kde/kde/kdegames/kiriki/src/scores.cpp:57

Test Plan: play a new game.

Reviewers: #kde_games, aacid

Reviewed By: aacid

Subscribers: aacid, chehrlic, schwarzer

Differential Revision: https://phabricator.kde.org/D11931