Revise git ignore files

Revise git ignore files

Revise our git ignores to match the current state of the tree, and include
entires in the top level for all of the 'dest' directories for all of the
architectures we claim to support.

Reviewed-on: http://gerrit.openafs.org/2
Reviewed-by: Derrick Brashear <shadow@gmail.com>
Verified-by: Simon Wilkinson <sxw@inf.ed.ac.uk>
(cherry picked from commit ba9ad6284528e669bfaacf0400b90fc08a5614e4)
Reviewed-on: http://gerrit.openafs.org/http://gerrit.openafs.org/172
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>