Returning NSXMLParser as response object on all platforms, and documenting the change (Thanks to Zac Bowling for the suggestion)

Don't set the responseParser delegate to nil in -dealloc

AFNetworking/AFXMLRequestOperation.h

@@ -34,6 +34,10 @@
  
  - `application/xml`
  - `text/xml`
+ 
+ ## Use With AFHTTPClient
+ 
+ When `AFXMLRequestOperation` is registered with `AFHTTPClient`, the response object in the success callback of `HTTPRequestOperationWithRequest:success:failure:` will be an instance of `NSXMLParser`. On platforms that support `NSXMLDocument`, you have the option to ignore the response object, and simply use the `responseXMLDocument` property of the operation argument of the callback.
  */
 @interface AFXMLRequestOperation : AFHTTPRequestOperation {
 @private

AFNetworking/AFXMLRequestOperation.m

@@ -122,7 +122,6 @@ static dispatch_queue_t xml_request_operation_processing_queue() {
 }
 
 - (void)dealloc {
-    _responseXMLParser.delegate = nil;
     [_responseXMLParser release];
     
 #if __MAC_OS_X_VERSION_MIN_REQUIRED
@@ -189,15 +188,9 @@ static dispatch_queue_t xml_request_operation_processing_queue() {
                 });
             }
         } else {
-#if __MAC_OS_X_VERSION_MIN_REQUIRED
-            if (success) {
-                success(self, self.responseXMLDocument);
-            }
-#else
             if (success) {
                 success(self, self.responseXMLParser);
             }
-#endif
         }
     };    
 }