don't call reexec.Init from chrootarchive

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)

Conflicts:
	daemon/graphdriver/aufs/aufs_test.go
		fixed conflict caused by imports

graph/pools_test.go

@@ -1,6 +1,14 @@
 package graph
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/docker/docker/pkg/reexec"
+)
+
+func init() {
+	reexec.Init()
+}
 
 func TestPools(t *testing.T) {
 	s := &TagStore{