libct: rm obsoleted comment

This was added by commit f2f16213e when runc-dmz was still a thing.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

libcontainer/setns_init_linux.go

@@ -150,11 +150,6 @@ func (l *linuxSetnsInit) Init() error {
 	// (otherwise the (*os.File) finaliser could close the wrong file). See
 	// CVE-2024-21626 for more information as to why this protection is
 	// necessary.
-	//
-	// This is not needed for runc-dmz, because the extra execve(2) step means
-	// that all O_CLOEXEC file descriptors have already been closed and thus
-	// the second execve(2) from runc-dmz cannot access internal file
-	// descriptors from runc.
 	if err := utils.UnsafeCloseFrom(l.config.PassedFilesCount + 3); err != nil {
 		return err
 	}