Add incr/decr to list of cbc symlinks

Change-Id: Ib35779d1c98c9316bacd142337e26ce2f8056a81
Reviewed-on: http://review.couchbase.org/43791
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>