callback: improve the resilience
callback: improve the resilience

- use a function to access the task name to simplify the code base
- avoid an error when dci_status is not set
- in case of error, push the task name in the jobstate comment.

Change-Id: I19f84745488eb22bbd6869d3ed3e2dd6227efb33

redhat-cip/dci-ansible,redhat-cip/dci-ansible