fix broken controller.servlet_response spec from #201

Author: kares

src/spec/ruby/jruby/rack/rails_booter_spec.rb

@@ -446,7 +446,10 @@ def booter.rails2?; false end
   let(:servlet_response) { org.jruby.rack.mock.MockHttpServletResponse.new }
 
   before :each do
-    request.stub(:env).and_return 'java.servlet_request' => servlet_request
+    request.stub(:env).and_return({
+        'java.servlet_request' => servlet_request,
+        'java.servlet_response' => servlet_response
+    })
     response.stub(:headers).and_return @headers = {}
   end