remove unused docId from result
Summary:
The doc id in result class is never set and
never read, so remove it. The id can be
retrieved from the document itself.
Test Plan: compiles
Reviewers: Baloo, bruns, ngraham
Reviewed By: Baloo, bruns, ngraham
Subscribers: ngraham, kde-frameworks-devel
Tags: Frameworks, Baloo
Differential Revision: https://phabricator.kde.org/D17298