Loopback interface not t brought up

Loopback interface was s not brought up when wemoved
to clone method of creating namespace. e. Adding it.
Also taking care of PR R comments.

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

libnetwork/sandbox/namespace_linux.go

@@ -25,7 +25,7 @@ var (
 	garbagePathMap   = make(map[string]bool)
 	gpmLock          sync.Mutex
 	gpmWg            sync.WaitGroup
-	gpmCleanupPeriod = 60
+	gpmCleanupPeriod = 60 * time.Second
 )
 
 // The networkNamespace type is the linux implementation of the Sandbox
@@ -57,7 +57,7 @@ func createBasePath() {
 
 func removeUnusedPaths() {
 	for {
-		time.Sleep(time.Duration(gpmCleanupPeriod) * time.Second)
+		time.Sleep(time.Duration(gpmCleanupPeriod))
 
 		gpmLock.Lock()
 		pathList := make([]string, 0, len(garbagePathMap))
@@ -78,16 +78,14 @@ func removeUnusedPaths() {
 
 func addToGarbagePaths(path string) {
 	gpmLock.Lock()
-	defer gpmLock.Unlock()
-
 	garbagePathMap[path] = true
+	defer gpmLock.Unlock()
 }
 
 func removeFromGarbagePaths(path string) {
 	gpmLock.Lock()
-	defer gpmLock.Unlock()
-
 	delete(garbagePathMap, path)
+	defer gpmLock.Unlock()
 }
 
 // GenerateKey generates a sandbox key based on the passed
@@ -120,6 +118,10 @@ func reexecCreateNamespace() {
 	if err := syscall.Mount("/proc/self/ns/net", os.Args[1], "bind", syscall.MS_BIND, ""); err != nil {
 		log.Fatal(err)
 	}
+
+	if err := loopbackUp(); err != nil {
+		log.Fatal(err)
+	}
 }
 
 func createNetworkNamespace(path string, osCreate bool) (*Info, error) {

libnetwork/sandbox/sandbox_linux_test.go

@@ -33,7 +33,7 @@ func newKey(t *testing.T) (string, error) {
 	}
 
 	// Set the rpmCleanupPeriod to be low to make the test run quicker
-	gpmCleanupPeriod = 2
+	gpmCleanupPeriod = 2 * time.Second
 
 	return name, nil
 }
@@ -152,7 +152,7 @@ func verifySandbox(t *testing.T, s Sandbox) {
 }
 
 func verifyCleanup(t *testing.T, s Sandbox) {
-	time.Sleep(time.Duration(gpmCleanupPeriod*2) * time.Second)
+	time.Sleep(time.Duration(gpmCleanupPeriod * 2))
 	if _, err := os.Stat(s.Key()); err == nil {
 		t.Fatalf("The sandbox path %s is not getting cleanup event after twice the cleanup period", s.Key())
 	}