Project: mesos
Issue MESOS-2995: Standardize use of Path 
As per the discussion in MESOS-2965, the use of the Path object should be standardized: * Functions which effectively use Paths (as strings) should instead take Paths. * Functions which modify and return Paths (as strings) should instead return Paths. * Extraneous uses of Path.value should be removed.
Story points: 3