Mirror MS_KERNMOUNT in ->mnt_flags

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index b0b15cc..ffa3843 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1701,7 +1701,7 @@
 {
 	int err;
 
-	mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD);
+	mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL);
 
 	down_write(&namespace_sem);
 	/* Something was mounted here while we slept */