Fix build failure

QStringList::join doesn't accept a QLatin1Char on my system. This fixes a build
regression introduced in commit fccffba04bbac0439583272b1c73151e9a00b0c6.

Change-Id: I98d8339032cb5ea315e09860aac3db91ab21d4c5
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>