Add Solaris 11 support.

  This commit is a simple change to Class['ntp::params'] which adds a
  selector to the default Solaris data so that the proper package name
  is managed on Solaris 11.

  With out this small change Solaris 11 hosts will attempt to improperly
  install package names following the old Solaris 10 standard.
Could you use `$::operatingsystemrelease` here?