D11643: Fix crash when device emits ready read after job is finished

[David Faure]

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

REPOSITORY
  R241 KIO

BRANCH
  master

REVISION DETAIL
  https://phabricator.kde.org/D11643

To: aacid, #frameworks, dfaure
Cc: #kde_connect, michaelh, ngraham