D21539: [FileIndexScheduler] Avoid emitting state changes multiple times

[Stefan Brüns]

bruns added reviewers: Baloo, ngraham, astippich.

REPOSITORY
  R293 Baloo

REVISION DETAIL
  https://phabricator.kde.org/D21539

To: bruns, #baloo, ngraham, astippich
Cc: kde-frameworks-devel, #baloo, gennad, domson, ashaposhnikov, michaelh, 
astippich, spoorun, ngraham, bruns, abrahams