Move HostUtil to pkg/volume/util/hostutil

This patch moves the HostUtil functionality from the util/mount package
to the volume/util/hostutil package.

All `*NewHostUtil*` calls are changed to return concrete types instead
of interfaces.

All callers are changed to use the `*NewHostUtil*` methods instead of
directly instantiating the concrete types.

pkg/kubemark/BUILD

@@ -35,6 +35,7 @@ go_library(
         "//pkg/volume/emptydir:go_default_library",
         "//pkg/volume/projected:go_default_library",
         "//pkg/volume/secret:go_default_library",
+        "//pkg/volume/util/hostutil:go_default_library",
         "//pkg/volume/util/subpath:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",

pkg/kubemark/hollow_kubelet.go

@@ -36,6 +36,7 @@ import (
 	"k8s.io/kubernetes/pkg/volume/emptydir"
 	"k8s.io/kubernetes/pkg/volume/projected"
 	"k8s.io/kubernetes/pkg/volume/secret"
+	"k8s.io/kubernetes/pkg/volume/util/hostutil"
 	"k8s.io/kubernetes/pkg/volume/util/subpath"
 	"k8s.io/kubernetes/test/utils"
 
@@ -75,7 +76,7 @@ func NewHollowKubelet(
 		OOMAdjuster:        oom.NewFakeOOMAdjuster(),
 		Mounter:            mount.New("" /* default mount path */),
 		Subpather:          &subpath.FakeSubpath{},
-		HostUtil:           &mount.FakeHostUtil{},
+		HostUtil:           hostutil.NewFakeHostUtil(nil),
 	}
 
 	return &HollowKubelet{