Comment 3 for bug 1535831

let's introduce /etc/fuel_issue file that is to be provided by fuel-release package,
then we can patch fuelclient so it reads /etc/fuel_issue instead of /etc/fuel_release.
Please avoid changing the format of /etc/fuel_release since the content of this file is used in many places and I'm afraid some of these places will fail to deal with 9.0-mu-*