D21119: [JobDialog] Also signal cancellation when window is closed by the user

[Aleix Pol Gonzalez]

apol accepted this revision.
This revision is now accepted and ready to land.

REPOSITORY
  R495 Purpose Library

REVISION DETAIL
  https://phabricator.kde.org/D21119

To: broulik, #plasma, apol
Cc: kde-frameworks-devel, michaelh, ngraham, bruns