Changed to usage of setter when setting the resultSet of the operation.

Prior to this change, I was not able to read records into the store as the respective member of operation is now called _resultSet.

I have not tested it with your code-base, but as the change is minor it should work. I would recommend testing against your Sencha Touch version and Sencha Touch 2.2.1 (I had this in use when the issue occured).