[Jenkinsfile] For failed builds, show stage name in slack message
[Jenkinsfile] For failed builds, show stage name in slack message

subutai-io/Subutai,subutai-io/base,subutai-io/base,subutai-io/base,subutai-io/base,subutai-io/Subutai,subutai-io/Subutai,subutai-io/Subutai,subutai-io/Subutai,subutai-io/Subutai