apt - security update

This update fixes a regression introduced in 0.8.10.3+squeeze5 where
apt would send invalid HTTP requests when sending If-Range queries.

For reference, the original advisory text follows.

The Google Security Team discovered a buffer overflow vulnerability in
the HTTP transport code in apt-get. An attacker able to
man-in-the-middle a HTTP request to an apt repository can trigger the
buffer overflow, leading to a crash of the http apt method binary, or
potentially to arbitrary code execution.

The following regression fixes were included in this update:

• Fix regression from the previous update in DLA-53-1
  when the custom apt configuration option for Dir::state::lists is set to a
  relative path (#762160).
• Fix regression in the reverificaiton handling of cdrom: sources that
  may lead to incorrect hashsum warnings. Affected users need to run
  “apt-cdrom add” again after the update was applied.
• Fix regression from the previous update in DLA-53-1
  when file:/// sources are used and those are on a different partition than
  the apt state directory.

For Debian 6 Squeeze, these issues have been fixed in apt version 0.8.10.3+squeeze6