fix logic of lnf loading
Summary:
mDefaultLnfConfig must be breeze, and mLnfConfig should be the
configured one, rather the other way around
Test Plan: plasma seems to start with proper icons now
Reviewers: Plasma, davidedmundson
Reviewed By: Plasma, davidedmundson
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D18260