make sure a Content-Length header exists and that the response.body i…

…s not nil before trying to call methods on it. Rack does not allow HTTP 204 responses to have a content-length header set. [#5038 state:resolved]

activeresource/lib/active_resource/base.rb

@@ -1318,7 +1318,7 @@ def create
       end
 
       def load_attributes_from_response(response)
-        if response['Content-Length'] != "0" && response.body.strip.size > 0
+        if !response['Content-Length'].blank? && response['Content-Length'] != "0" && !response.body.nil? && response.body.strip.size > 0
           load(self.class.format.decode(response.body))
         end
       end