emit_releases_file needed to be updated to support centos8 and
integration pipeline.
I needed to make the script distro aware, then distringuish between
distros to get the proper repo and hash in get_dlrn_hash function.
The tests have been only partially updated: I updated the success script
to cover the centos8 case, and accountfor the change in signature for
get_dlrn_hash, but the rest of the workflow is exaclty the same either
if we are in centos7 or centos8, so I did not add any additional checks.
Change-Id: I26799d5e6a3ed404b4a29be621c5871ef9be6e4c
50203ab44a