fix for https://github.com/ansible/ansible/issues/4795
Incorrect changed result in cron module.
Report changed=False if no cron is removed:wq
return True/False from remove_job_file()
revised fix for https://github.com/ansible/ansible/issues/4795
Merge pull request #4797 from weaselkeeper/devel

fix for https://github.com/ansible/ansible/issues/4795 (incorrect changed result in cron module)