Summary:
If we don't emit result, the ExecuteCompositeJob doesn't relise that
it's failing and keeps the dangling object. Calling stop all processes
would result in a crash then.

Test Plan:
* run app
* run app again
* choose to kill the first instance
* stop all processes

Reviewers: #kdevelop, mwolff

Reviewed By: #kdevelop, mwolff

Subscribers: mwolff, kdevelop-devel

Differential Revision: https://phabricator.kde.org/D10874