new files for FreeBSD packaging at 1.6.0pre3

new files for FreeBSD packaging at 1.6.0pre3

Packaging for use with FreeBSD's Ports Collection.
The directory layout is flattened, and a couple of files that do not
make sense here are not included.
The afsd rc script lives in packaging/ as it is not runnable in
its committed form, it requires variable substitution that occurs
at install-time from the Ports Collection.

Change-Id: I72d6c2ee7106611b0ec9bfe3e47a471ed66b7255
Reviewed-on: http://gerrit.openafs.org/4351
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>