Fix a building issue
Summary:
Build regression introduced in D26847
https://build.neon.kde.org/job/bionic_unstable_kde_user-manager_bin_amd64/99/console
Test Plan: Builds
Reviewers: Plasma, ngraham, rikmills, jriddell
Reviewed By: jriddell
Subscribers: jriddell, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D26893