scheduler: Update comment
scheduler: Update comment

The function being referenced here no longer exists.

Signed-off-by: Aaron Lehmann <8ecfc6017a87905413dcd7d63696a2a4c351b604@docker.com>

alyyousuf7/swarmkit,cheyang/swarmkit,docker/swarmkit,sungwonh/swarmkit,cheyang/swarmkit,docker/swarmkit,AliyunContainerService/swarmkit,AliyunContainerService/swarmkit,dperny/swarmkit-1,jlhawn/swarmkit,jlhawn/swarmkit,alyyousuf7/swarmkit,sungwonh/swarmkit,dperny/swarmkit-1