os:: Update the Ubuntu-to-Debian matching

For Stanford repositories, we’ve got a list of Ubuntu dsitros that map to Debian distros.  That list is updated.

templates/os/sources/stanford.list.erb

@@ -3,7 +3,11 @@
    # Map Ubuntu distributions to Debian distributions since we don't
    # currently have any repositories targeted for Ubuntu releases.
    if @operatingsystem == 'Ubuntu'
-     if (@lsbdistcodename =~ /raring|trusty/)
+     if (@lsbdistcodename =~ /xenial/)
+       dist = 'stretch'
+     elsif (@lsbdistcodename =~ /wily|vivid|utopic|trusty/)
+       dist = 'jessie'
+     elsif (@lsbdistcodename =~ /saucy|raring|quantal|precise|oneiric/)
        dist = 'wheezy'
      else
        dist = 'squeeze'