p7zip - security update

Alexander Cherepanov discovered that p7zip is susceptible to a
directory traversal vulnerability. While extracting an archive, it
will extract symlinks and then follow them if they are referenced in
further entries. This can be exploited by a rogue archive to write
files outside the current directory.

For the oldoldstable distribution (squeeze), this problem has been
fixed in version 9.04~dfsg.1-1+deb6u1.

For the oldstable distribution (wheezy) and stable distribution
(jessie), this problem will be fixed soon.