kservice failures with Qt 5.4

[Jonathan Riddell]

kservice 5.15 and git master is failing a test with Qt 5.4 which passes with 5.5

with Qt 5.4
https://build.kde.org/job/kservice%20master%20stable-kf5-qt5/PLATFORM=Linux,compiler=gcc/89/console

with Qt 5.5
https://build.kde.org/job/kservice%20master%20kf5-qt5/PLATFORM=Linux,compiler=gcc/94/console

alas Kubuntu is still using Qt 5.4.  Is this likely to cause problems?

Jonathan