Don't use initialiser list syntax for reference

Summary:
Initialiser lists don't work for member references in gcc 4.8, see:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50025

(This issue is apparently fixed in gcc 4.9, but at least my distro
still ships 4.8 by default.)

This syntax was originally introduced in:
ba7128b30850594c7efb258d1794e377eede364a

Reviewers: Kube, cmollekopf, aacid

Reviewed By: Kube, cmollekopf

Subscribers: aacid

Differential Revision: https://phabricator.kde.org/D4516