Fix for redhat clone with yum rpm, same strategy as the debian with apt-get and .deb file.
When the rpm repo is used an old 0.11 version is used that cannot update/upgrade to the latest 0.12 releases.
Now the rpm is downloaded and installed from http://scalasbt.artifactoryonline.com/scalasbt/sbt-native-packages/org/scala-sbt/sbt/ as default