search in the new location for knsrc files

Summary:
search in the new knsrc location, still fallback to the old one for
compatibility

Test Plan: tested with files in both locations

Reviewers: Plasma, leinir

Reviewed By: leinir

Subscribers: leinir, kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D21183