Fix copyright dates

Script: https://gist.github.com/4510417
Change-Id: If20e0d1f940981e1b3a4c5971fa99a4a1991ce4a
Reviewed-on: http://review.couchbase.org/23873
Reviewed-by: Matt Ingenthron <matt@couchbase.com>
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>