Update libkv godeps

Signed-off-by: Jana Radhakrishnan <mrjana@docker.com>

libnetwork/Godeps/Godeps.json

@@ -146,7 +146,7 @@
 		},
 		{
 			"ImportPath": "github.com/docker/libkv",
-			"Rev": "9d9710dcf6419a58455d0a80e0a8a21ca5f21a94"
+			"Rev": "4ca160cf21d4e097725d93a72d7b3937c537cdc2"
 		},
 		{
 			"ImportPath": "github.com/godbus/dbus",

libnetwork/Godeps/_workspace/src/github.com/docker/libkv/store/boltdb/boltdb.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"os"
 	"path/filepath"
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -43,6 +44,7 @@ type BoltDB struct {
 	// PersistConnection flag provides an option to override ths behavior.
 	// ie: open the connection in New and use it till Close is called.
 	PersistConnection bool
+	sync.Mutex
 }
 
 const (
@@ -130,6 +132,8 @@ func (b *BoltDB) Get(key string) (*store.KVPair, error) {
 		db  *bolt.DB
 		err error
 	)
+	b.Lock()
+	defer b.Unlock()
 
 	if db, err = b.getDBhandle(); err != nil {
 		return nil, err
@@ -169,6 +173,9 @@ func (b *BoltDB) Put(key string, value []byte, opts *store.WriteOptions) error {
 		db      *bolt.DB
 		err     error
 	)
+	b.Lock()
+	defer b.Unlock()
+
 	dbval := make([]byte, libkvmetadatalen)
 
 	if db, err = b.getDBhandle(); err != nil {
@@ -201,6 +208,9 @@ func (b *BoltDB) Delete(key string) error {
 		db  *bolt.DB
 		err error
 	)
+	b.Lock()
+	defer b.Unlock()
+
 	if db, err = b.getDBhandle(); err != nil {
 		return err
 	}
@@ -224,6 +234,8 @@ func (b *BoltDB) Exists(key string) (bool, error) {
 		db  *bolt.DB
 		err error
 	)
+	b.Lock()
+	defer b.Unlock()
 
 	if db, err = b.getDBhandle(); err != nil {
 		return false, err
@@ -253,6 +265,9 @@ func (b *BoltDB) List(keyPrefix string) ([]*store.KVPair, error) {
 		db  *bolt.DB
 		err error
 	)
+	b.Lock()
+	defer b.Unlock()
+
 	kv := []*store.KVPair{}
 
 	if db, err = b.getDBhandle(); err != nil {
@@ -299,6 +314,8 @@ func (b *BoltDB) AtomicDelete(key string, previous *store.KVPair) (bool, error)
 		db  *bolt.DB
 		err error
 	)
+	b.Lock()
+	defer b.Unlock()
 
 	if previous == nil {
 		return false, store.ErrPreviousNotSpecified
@@ -337,6 +354,9 @@ func (b *BoltDB) AtomicPut(key string, value []byte, previous *store.KVPair, opt
 		db      *bolt.DB
 		err     error
 	)
+	b.Lock()
+	defer b.Unlock()
+
 	dbval := make([]byte, libkvmetadatalen)
 
 	if db, err = b.getDBhandle(); err != nil {
@@ -391,6 +411,9 @@ func (b *BoltDB) AtomicPut(key string, value []byte, previous *store.KVPair, opt
 
 // Close the db connection to the BoltDB
 func (b *BoltDB) Close() {
+	b.Lock()
+	defer b.Unlock()
+
 	if !b.PersistConnection {
 		b.reset()
 	} else {
@@ -405,6 +428,9 @@ func (b *BoltDB) DeleteTree(keyPrefix string) error {
 		db  *bolt.DB
 		err error
 	)
+	b.Lock()
+	defer b.Unlock()
+
 	if db, err = b.getDBhandle(); err != nil {
 		return err
 	}