Patch up FreeBSD-10 support

Patch up FreeBSD-10 support

The auto-guessing code for sysnames produces *_fbsd_100, so we can't
just claim that we'll be *_fbsd_1000 for kicks.
Revert back to the old behavior so as to be less disruptive.

Reviewed-on: http://gerrit.openafs.org/7595
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 44ca4aa90ef101fb13b3b5327ca19381b5464fb3)

Change-Id: I302b9f36913b6cd86f65b7263c85d91745330ae6
Reviewed-on: http://gerrit.openafs.org/8341
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>