Kill the last mutant in Zero::Request:AcceptType

spec/unit/zero/request/accepttype/preferred_spec.rb

@@ -24,6 +24,7 @@ describe Zero::Request::AcceptType, '#preferred' do
     it { subject.new(nil).preferred.should                     == '*/*' }
     it { subject.new('').preferred.should                      == '*/*' }
     it { subject.new('text / html').preferred.should           == html  }
+    it { subject.new("#{html};q=0.9,#{json}").preferred.should == json  }
   end
 
 #  context 'with mapping' do