Update containerd to f2a20ead83.

Signed-off-by: Lantao Liu <lantaol@google.com>

vendor/github.com/Microsoft/hcsshim/internal/safefile/safeopen.go

@@ -87,7 +87,7 @@ func OpenRoot(path string) (*os.File, error) {
 
 func ntRelativePath(path string) ([]uint16, error) {
 	path = filepath.Clean(path)
-	if strings.Contains(":", path) {
+	if strings.Contains(path, ":") {
 		// Since alternate data streams must follow the file they
 		// are attached to, finding one here (out of order) is invalid.
 		return nil, errors.New("path contains invalid character `:`")