Provisioning openSuSE VMs with a populated /home/qt.cache creates
flaky crashes of plasmashell during KDE/Plasma startup.
This scrip wipes the directory at the end of provisioning
Pick-to: 6.4 6.3 6.2 5.15
Fixes: COIN-897
Change-Id: If61f86843e7b81dfee85610b1cd73bb15ce26658
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>