fix bug 1069718 - no longer need devtoolset SCL on RHEL/CentOS
Merge pull request #2384 from rhelmer/bug1069718-remove-devtoolset-scl

fix bug 1069718 - no longer need devtoolset SCL on RHEL/CentOS
fixes bug 804253 - remove settings.OPERATING_SYSTEMS
Merge pull request #2385 from peterbe/bug-804253-remove-settingsoperating_systems

fixes bug 804253 - remove settings.OPERATING_SYSTEMS