Remove some extra stuff from autotools' 'dist' target

Change-Id: I0a5c7f21cd795f01de9f85d13f442924f3ef5116
Reviewed-on: http://review.couchbase.org/43691
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>