D25117: file ioslave: stop copying as soon as the ioslave is killed

[Méven Car]

meven added a task: T11627: Improve KIO asynchronicity.

REPOSITORY
  R241 KIO

REVISION DETAIL
  https://phabricator.kde.org/D25117

To: meven, #frameworks, dfaure, ngraham, apol
Cc: apol, kde-frameworks-devel, LeGast00n, GB_2, michaelh, ngraham, bruns