disable unattended-upgrades for images

Change-Id: Idc4bd64f14046150307746e619d88df079ab95af
diff --git a/ubuntu-14.04/http/preseed-lvm.cfg b/ubuntu-14.04/http/preseed-lvm.cfg
index 81c7bac..fbaf984 100644
--- a/ubuntu-14.04/http/preseed-lvm.cfg
+++ b/ubuntu-14.04/http/preseed-lvm.cfg
@@ -51,7 +51,7 @@
 
 d-i pkgsel/include string openssh-server
 d-i pkgsel/install-language-support boolean false
-d-i pkgsel/update-policy select unattended-upgrades
+d-i pkgsel/update-policy select none
 popularity-contest popularity-contest/participate boolean false
 
 d-i pkgsel/upgrade select none