translations are not loaded if hook contains line breaks

This issue rises on bug #982924.

if update-notifier hook contains line breaks(.), translations are not loaded.

How to reproduce:
 1. place "ecryptfs-record-passphrase" file in /var/lib/update-notifier/user.d/
 2. place "ecryptfs-utils.mo" file in /usr/share/locale-langpack/"YOUR_LOCALE"/LC_MESSAGES/
 3. remove ~/.config/update-notifier/hooks_seen and ~/.ecryptfs/.wrapped-passphrase.recorded (with care)
 4. restart update-notifier

Expected result:
 All messages in the dialogue are translated.

Actual result:
 The description is not translated, but only the title is translated.

with removing line breaks(.) and re-generating .pot and .mo, the issue is not reproducible.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: update-notifier 0.126
ProcVersionSignature: Ubuntu 3.5.0-17.28-generic 3.5.5
Uname: Linux 3.5.0-17-generic x86_64
ApportVersion: 2.6.1-0ubuntu6
Architecture: amd64
Date: Tue Nov 6 04:35:23 2012
EcryptfsInUse: Yes
InstallationDate: Installed on 2012-10-03 (33 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Beta amd64 (20120926)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=ja_JP.UTF-8
 SHELL=/bin/bash
SourcePackage: update-notifier
UpgradeStatus: No upgrade log present (probably fresh install)