[SRU] fix end date calculation for releases in june

Binary package hint: python-apt

Nominating for SRU in lucid the following fix:
===
python-apt (0.7.95ubuntu2) maverick; urgency=low

  * apt/utils.py:
    - fix end date calculation for releases in june
===

This is visible in software-center with the following error:
Traceback (most recent call last):
[...]
    self.app.appname or self.app.pkgname, self.app.pkgname, self.component, self.channelfile)
  File "/usr/share/software-center/softwarecenter/distro/Ubuntu.py", line 162, in get_maintenance_status
    support_end_month_str = locale.nl_langinfo(getattr(locale,"MON_%d" % support_end_month))
AttributeError: 'module' object has no attribute 'MON_0'

Rationale:
- A user cannot access the detailed informations about a software in software center. This is reproducible with canonical partners software released in june (latest release of app-install-data-partner in lucid)
- Trivial fix.

TEST CASE:
1. Install app-install-data-partner 12.10.04.3 (in lucid-proposed)
2. Open a terminal and run software-center and go to "Get Software / Canonical Partners"
3. Select a software on the right and click on "More info"

VERIFICATION DONE:
- You can access the detailed information.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: python-apt 0.7.94.2ubuntu6.1
ProcVersionSignature: Ubuntu 2.6.32-22.36-generic 2.6.32.11+drm33.2
Uname: Linux 2.6.32-22-generic i686
Architecture: i386
Date: Tue Jul 6 23:32:58 2010
InstallationMedia: Ubuntu 10.04 "Lucid Lynx" - Release Candidate i386 (20100419.1)
ProcEnviron:
 LANG=fr_FR.utf8
 SHELL=/bin/bash
SourcePackage: python-apt