Add initial logging to libcontainer

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

libcontainer/nsinit/nsinit.go

@@ -2,6 +2,7 @@ package nsinit
 
 import (
 	"github.com/dotcloud/docker/pkg/libcontainer"
+	"log"
 )
 
 // NsInit is an interface with the public facing methods to provide high level
@@ -16,11 +17,13 @@ type linuxNs struct {
 	root           string
 	commandFactory CommandFactory
 	stateWriter    StateWriter
+	logger         *log.Logger
 }
 
-func NewNsInit(command CommandFactory, state StateWriter) NsInit {
+func NewNsInit(command CommandFactory, state StateWriter, logger *log.Logger) NsInit {
 	return &linuxNs{
 		commandFactory: command,
 		stateWriter:    state,
+		logger:         logger,
 	}
 }