Autogenerate a Debian changelog for correct package versioning

Autogenerate a Debian changelog for correct package versioning

The Debian packaging infrastructure takes the package version from the
most recent entry in the changelog file.  Change the changelog file to
a template and add an entry to the top that will be set to the current
version of OpenAFS, with a Debian revision that will sort before any
official package.

Change-Id: Ic7fb1d30be10210b7d032cdc49a963410997db82
Reviewed-on: http://gerrit.openafs.org/1749
Tested-by: Russ Allbery <rra@stanford.edu>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>