Fix containment of java::config

In 0dcd91b the `anchor` pattern was
removed, but not replaced with anything and thus broke the containment
of `java::config`.  This restores the original behaviour by using
`contain`.

As noted in the code comment, the declaration remains in the same place
in the code as evaluation order is important.  `java::config` is a
private class and relies on variables from the base class's scope having
been set before it is evaluated.

Author: alexjfisher

manifests/init.pp

@@ -135,6 +135,8 @@
     ensure          => $version,
     install_options => $package_options,
     name            => $use_java_package_name,
+    before          => Class['java::config'],
   }
-  -> class { 'java::config': }
+
+  contain java::config # NB evalutation order is important here as the config class relies on variables from the base class having been set before it's evaluated.
 }