Bug 1331747

Description of problem:
In some cases (such as content view update), when foreman-tasks is not running, the task can and up with success result but pending state, and block the other actions to be performed

Version-Release number of selected component (if applicable):
satellite 6.2.0 beta

How reproducible:
On special occasions

Steps to Reproduce:
1. stop foreman-tasks service
2. rename a content view
3. start the foreman-tasks

Actual results:
the content view action ends up in success result but pending state

Expected results:
the content view action finishes once foreman-tasks start

Additional info:
A workaround is:

```
cat <<SCRIPT | foreman-rake console
ForemanTasks::Task.where(:state => :planned, :result => :success).map do |task|
  task.update_attributes(:state => 'stopped')
end
SCRIPT
```