mowed down a man and his dog in his van because the rottweiler pooed on his driveway, a court has heard.Alexander McKinley is said to have carried out a life-threatening assault on Dean Johnstone by deliberately knocking him down in his van.And a witness has told how he saw the incident unfold in front of him - and heard the dog "yelping" in pain afterwards.Robert Duffy, 66, was giving evidence at McKinley's Paisley Sheriff Court trial.He denies assaulting Mr Johnstone by driving a Vauxhall