Add ignore socket test

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

vendor/github.com/containerd/continuity/fs/fstest/file.go

@@ -2,6 +2,7 @@ package fstest
 
 import (
 	"io/ioutil"
+	"net"
 	"os"
 	"path/filepath"
 	"time"
@@ -107,6 +108,18 @@ func Link(oldname, newname string) Applier {
 //	}
 //}
 
+func CreateSocket(name string, perm os.FileMode) Applier {
+	return applyFn(func(root string) error {
+		fullPath := filepath.Join(root, name)
+		ln, err := net.Listen("unix", fullPath)
+		if err != nil {
+			return err
+		}
+		defer ln.Close()
+		return os.Chmod(fullPath, perm)
+	})
+}
+
 // Apply returns a new applier from the given appliers
 func Apply(appliers ...Applier) Applier {
 	return applyFn(func(root string) error {

vendor/github.com/containerd/continuity/fs/fstest/testsuite.go

@@ -74,6 +74,7 @@ var (
 		Symlink("libnothing.so", "/usr/local/lib/libnothing.so.2"),
 		CreateDir("/home", 0755),
 		CreateDir("/home/derek", 0700),
+		CreateDir("/var/run/socket", 0700),
 	)
 
 	// basicTest covers basic operations