Receipt from rent of vacant land

1. It was right from your side to show the income from vacant land as a part of your "Income from House property". It would be prudent for you to show the correct treatment of such rental income from land and again not commit the same mistake. 
2. There may be a possibility that the same might get the attention from the department side but that should not be the reason for you to again commit the same mistake. 
3. Whatever you have done during the year is correct. Make sure you compute additional income tax payable if any on account of such misrepresentation and have an awareness that it does not deviate too much. However such misrepresentation normally happens and if the transactions are genuine it should not be a problem. 
Please correct me if the above solution has an alternative view. 

What if I tell you that I visited that area and there is also a small room (enough to make it a house property) on that land. Due to which you treated this income as income from house property last year and you should do the same in this year.