(fact-155) Fix operatingsystemrelease on Solaris 11

since facter 1.7.0 we have an explicit `operatingsystemrelase` fact for Solaris so we do not just use the `kernel` fact anymore. Unfortunately the fact does only work on Solaris 10 and not on Solaris 11. So while on Solaris 10 we have a meaningful value now, we have a copy of the `kernel` fact on Solaris 11.

Update the fact to print a meaningful value  on Solaris 11 (strictly speaking this is a change in behaviour) and also implement an `operatingsystemmajrelease` fact to easily check for Solaris 10 or Solaris 11 in manifests.