Clean up umount targets (tiann#2386)

Author: aviraxp

kernel/core_hook.c

@@ -555,11 +555,11 @@ int ksu_handle_setuid(struct cred *new, const struct cred *old)
 	try_umount("/system", true, 0);
 	try_umount("/vendor", true, 0);
 	try_umount("/product", true, 0);
+	try_umount("/system_ext", true, 0);
 	try_umount("/data/adb/modules", false, MNT_DETACH);
 
 	// try umount ksu temp path
 	try_umount("/debug_ramdisk", false, MNT_DETACH);
-	try_umount("/sbin", false, MNT_DETACH);
 
 	return 0;
 }