Initialise QML monitor values

Summary:
m_indexerState would not be initialised and m_totalFiles would be
garbage values if baloo_file wasn't running. We want to initialise
everything.

Test Plan: Compiles

Reviewers: ngraham

Reviewed By: ngraham

Subscribers: kde-frameworks-devel, Baloo

Tags: Frameworks, Baloo

Differential Revision: https://phabricator.kde.org/D25788