Simplify package name handling

f614db2 removed the use of
$rubygem_katello_ostree variable, but not its definition.

We also don't want to hard fail because we sometimes want to compile on
other distros. The most common use case is CI testing our installer by
running it with --help. Since that happens on Travis (which is Ubuntu)
it hard fails.

manifests/params.pp

@@ -1,25 +1,12 @@
 # Katello Default Params
 class katello::params {
 
-  case $::osfamily {
-    'RedHat': {
-      case $::operatingsystem {
-        'Fedora': {
-          $rubygem_katello = 'rubygem-katello'
-          $rubygem_katello_ostree ='rubygem-katello_ostree'
-        }
-        default: {
-          $rubygem_katello = 'tfm-rubygem-katello'
-          $rubygem_katello_ostree ='tfm-rubygem-katello_ostree'
-        }
-      }
-
-      $package_names = ['katello', $rubygem_katello]
-    }
-    default: {
-      fail("${::hostname}: This module does not support osfamily ${::osfamily}")
-    }
+  if $::operatingsystem == 'Fedora' {
+    $rubygem_katello = 'rubygem-katello'
+  } else {
+    $rubygem_katello = 'tfm-rubygem-katello'
   }
+  $package_names = ['katello', $rubygem_katello]
 
   $deployment_url = '/katello'