Update to latest cadvisor - cleanup mesos/rkt

Change-Id: Ib5ae0cb13b93f8c87bb74e3ba33040df5f3d6a6f

vendor/github.com/google/cadvisor/fs/fs.go

@@ -91,23 +91,6 @@ type RealFsInfo struct {
 	fsUUIDToDeviceName map[string]string
 }
 
-type Context struct {
-	// docker root directory.
-	Docker  DockerContext
-	RktPath string
-	Crio    CrioContext
-}
-
-type DockerContext struct {
-	Root         string
-	Driver       string
-	DriverStatus map[string]string
-}
-
-type CrioContext struct {
-	Root string
-}
-
 func NewFsInfo(context Context) (FsInfo, error) {
 	mounts, err := mount.GetMounts(nil)
 	if err != nil {
@@ -410,8 +393,13 @@ func (self *RealFsInfo) GetFsInfoForPath(mountSet map[string]struct{}) ([]Fs, er
 				klog.V(5).Infof("got devicemapper fs capacity stats: capacity: %v free: %v available: %v:", fs.Capacity, fs.Free, fs.Available)
 				fs.Type = DeviceMapper
 			case ZFS.String():
-				fs.Capacity, fs.Free, fs.Available, err = getZfstats(device)
-				fs.Type = ZFS
+				if _, devzfs := os.Stat("/dev/zfs"); os.IsExist(devzfs) {
+					fs.Capacity, fs.Free, fs.Available, err = getZfstats(device)
+					fs.Type = ZFS
+					break
+				}
+				// if /dev/zfs is not present default to VFS
+				fallthrough
 			default:
 				var inodes, inodesFree uint64
 				if utils.FileExists(partition.mountpoint) {