Change spec to reflect new method behavior.

After commit 6219578, iTunes feeds are processed as standard RSS.  Because of this they shouldn't respond to iTunes RSS Entry methods.

spec/feedzirra/feed_spec.rb

@@ -49,11 +49,14 @@
         feed.entries.size.should == 5
       end      
 
-      it "should parse an itunes feed" do
+      it "should parse an itunes feed as a standard RSS feed" do
         feed = Feedzirra::Feed.parse(sample_itunes_feed)
         feed.title.should == "All About Everything"
-        feed.entries.first.published.to_s.should == "Wed, 15 Jun 2005 19:00:00 GMT"
-        feed.entries.first.itunes_author.should == "John Doe"
+        feed.entries.first.published.should == Time.parse("Wed, 15 Jun 2005 19:00:00 GMT")
+
+        # Since the commit 621957879, iTunes feeds will be parsed as standard RSS, so this
+        # entry should now not have a method for itunes_author.
+        feed.entries.first.should_not respond_to(:itunes_author)
         feed.entries.size.should == 3
       end
     end