minion: Retry after scheduler errors
minion: Retry after scheduler errors

Due to a bug, if the scheduler returned an error when listing
containers, we would never try again.

kelda/kelda,kklin/kelda,stevenlin598/quilt,ZhongtianWang/quilt,LuiseV/quilt,stevenlin598/quilt,mmussomele/quilt,kklin/quilt,quilt/quilt,secant/quilt,kelda/kelda,NetSys/quilt,LuiseV/quilt,LuiseV/quilt,tejasmanohar/quilt,akshayknarayan/quilt,ejj/quilt-dev,mmussomele/quilt,ejj/quilt-dev,secant/quilt,quilt/quilt,NetSys/quilt,PenguinToast/quilt,tejasmanohar/quilt,kayousterhout/quilt,kklin/kelda,kelda/kelda,kayousterhout/quilt,akshayknarayan/quilt,PenguinToast/quilt,kklin/quilt,kklin/kelda,NetSys/quilt,kklin/kelda,LuiseV/quilt,stevenlin598/quilt,stevenlin598/quilt,mmussomele/quilt,kayousterhout/quilt,quilt/quilt,secant/quilt,quilt/quilt,tejasmanohar/quilt,ejj/quilt-dev,ejj/quilt-dev,akshayknarayan/quilt,kayousterhout/quilt,secant/quilt,PenguinToast/quilt,PenguinToast/quilt,mmussomele/quilt,stevenlin598/quilt,kklin/quilt,PenguinToast/quilt,akshayknarayan/quilt,ZhongtianWang/quilt,mmussomele/quilt,mmussomele/quilt,kelda/kelda,secant/quilt,ZhongtianWang/quilt,stevenlin598/quilt,kklin/quilt,tejasmanohar/quilt,LuiseV/quilt,ZhongtianWang/quilt,NetSys/quilt,NetSys/quilt