Drop the state_directory field (#6528)
Drop the state_directory field (#6528)

This field is not used and is optional. So we have to make it optional or drop it. Since it's not used, I am droping it.
gsantovena/marathon,mesosphere/marathon,gsantovena/marathon,gsantovena/marathon,mesosphere/marathon,mesosphere/marathon,mesosphere/marathon,gsantovena/marathon,mesosphere/marathon,gsantovena/marathon