Make supervisor.go to compile without libcontainer.

Signed-off-by: David Calavera <david.calavera@gmail.com>

supervisor.go

@@ -8,7 +8,6 @@ import (
 	"time"
 
 	"github.com/Sirupsen/logrus"
-	"github.com/docker/containerd/linux"
 	"github.com/docker/containerd/runtime"
 	"github.com/opencontainers/runc/libcontainer"
 )
@@ -19,7 +18,7 @@ func NewSupervisor(stateDir string, concurrency int) (*Supervisor, error) {
 		return nil, err
 	}
 	// register counters
-	r, err := linux.NewRuntime(stateDir)
+	r, err := newRuntime(stateDir)
 	if err != nil {
 		return nil, err
 	}

supervisor_linux.go

@@ -0,0 +1,9 @@
+// +build libcontainer
+
+package containerd
+
+import "github.com/docker/containerd/runtime"
+
+func newRuntime(stateDir string) (runtime.Runtime, error) {
+	return linux.NewRuntime(stateDir)
+}

supervisor_unsupported.go

@@ -0,0 +1,13 @@
+// +build !libcontainer
+
+package containerd
+
+import (
+	"errors"
+
+	"github.com/docker/containerd/runtime"
+)
+
+func newRuntime(stateDir string) (runtime.Runtime, error) {
+	return nil, errors.New("Unsupported runtime")
+}