no upgrade with Unattended-upgrades

[LORAIN]

Apt-get upgrade Problem Unattended-upgrades

Unattended upgrade returned: None

Packages that are upgraded:

Packages with upgradable origin but kept back:
 cron desktop-file-utils

Unattended-upgrades log:
Initial blacklisted packages:
Starting unattended upgrades script
Allowed origins are: ['o=Ubuntu,a=precise', 'o=Ubuntu,a=precise-stable', 'o=Ubuntu,a=precise-security', 'o=Ubuntu,a=precise-updates', 'o=Ubuntu,a=precise-ocracoke', 'o=Canonical,a=precise', 'o=GetDeb,a=precise-getdeb', 'o=Google\\, Inc.,a=stable', 'o=LP-PPA-app-review-board,a=precise']
Package 'cron' has conffile prompt and needs to be upgraded manually
Package 'desktop-file-utils' has conffile prompt and needs to be upgraded manually
package 'cron' not upgraded
package 'desktop-file-utils' not upgraded
Packages that are auto removed: ''
Packages that are upgraded:

upgraded manually sudo apt-get update && sudo apt-get dist-upgrade no upgrades

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: cron 3.0pl1-120ubuntu3
ProcVersionSignature: Ubuntu 3.2.0-55.85-generic-pae 3.2.51
Uname: Linux 3.2.0-55-generic-pae i686
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: i386
Date: Fri Nov 1 10:23:18 2013
DistributionChannelDescriptor:
 # This is a distribution channel descriptor
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-yanshui-precise-i386-20120615-0
InstallationMedia: Ubuntu 12.04 "Precise" - Failed to find casper uuid.conf in 'binary/casper/initrd.img-3.2.0-25-generic-pae.old-dkms' LIVE Binary 20120615-03:22
MarkForUpload: True
SourcePackage: cron
UpgradeStatus: No upgrade log present (probably fresh install)
mtime.conffile..etc.default.cron: 2013-09-30T23:47:00.986005

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.