Fixes cookie domain specification

if the domain given in HTTP_HOST variable happens to have a port
specification. Technically, the port specification should not be included in
the domain spec given in the cookie.

(And for the record, that makes no sense to me, seeing as a cookie would
otherwise be valid for all servers on any ports at a particular domain).
Merge pull request #719 from greezybacon/issue/cookie-variant-port

Fixes cookie domain specification

Reviewed-By: Peter Rotich <peter@osticket.com>