Remove unused cbsasl files from distribution

This also allows us to cleanly merge the newer cbsasl distribution by
allowing to determine a better delta

Change-Id: Ie89c4952afb68f13409825069ae3e22d90935e9f
Reviewed-on: http://review.couchbase.org/43792
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>