Redirect domainname.com. to domainname.com - full stop at the ned of the url

Hi,

Ive had a request from a seo company saying that the domian name we have is showing up as a duplicate with a full stop on the end, see below. They want me to 301 redirect
www.mydomainname.com. to www.mydomainname.com within nginx.

www.mydomainname.com and www.mydomainname.com.

Ive checked google and youtube and they don't seem to do it. i.e if I go to to the link below the full stop stays within the url.
http://www.youtube.com
http://www.youtube.com.
http://www.youtube.com./watch?v=_NQLmOo6Wqg

So basically I want to know is this an actual issue and how do i rectify it within nginx. Its the first time i have had this issue, my nginx config is pretty basic, see below:

listen 80;
server_name www.mydomainname.com;;

Any help appreciated