Change validation on Boolean, to reflect changes in RDF.rb.

Author: gkellogg

spec/literal_spec.rb

@@ -15,8 +15,8 @@
       %w(0 false)
     ]
     it_behaves_like 'RDF::Literal validation', RDF::XSD.boolean,
-      %w(true false tRuE FaLsE 1 0),
-      %w(foo 10)
+    %w(true false 1 0),
+    %w(foo 10) + ['true false', 'true foo', 'tRuE' 'FaLsE']
   end
 
   describe RDF::Literal::Integer do