debian/rules: add hardening=+all

Because of dpkg-buildflags we already get most of the hardening
features, +all adds -fPIE and ld -z now

Thanks: Simon Ruderich, Markus Waldeck
apt-get: Create the temporary downloaded changelog inside tmpdir

The code is creating a secure temporary directory, but then creates
the changelog alongside the tmpdir in the same base directory. This
defeats the secure tmpdir creation, making the filename predictable.

Inject a '/' between the tmpdir and the changelog filename.
releasing package apt version 1.0.9.2
implement the updated build profile spec