There certainly wasn't a foul on Johnson, but that aside I don't think it was a penalty.
Hoilett put his leg at full stretch not to get control of the ball but to stick it in front of Vickers so when he went to clear it he'd make contact. Hoilett knew exactly what he was doing, don't like to see those given.
As it happens, Aberdeen were unfortunate a month or so ago away at St Mirren when they gave away a penalty of a very similar nature in the 95th minute. I thought they were hard done by then.
No consistency right enough and Aberdeen have lost out twice.