Whether this was in any way related to the increase in the minimum wage depends entirely on which jobs were lost. If they are mostly burgerflipper jobs, then you could say that this was an effect. Of course, it also could be due to a decline in the percentage of people who depend on McDonald's for their meals.
The line at the McDonald's down the street from me has been much shorter for quite a while. A year ago, it extended out so far it blocked traffic.