Ensure no leading or trailing whitespace on the remote_addr

If reading the remote_addr from X-Forwarded-For header, ensure that there is
no leading or trailing whitespace. If ip_binding is enabled for staff
sessions, this could cause unnecessary logouts
Merge pull request #665 from greezybacon/issue/trim-remote-addr

Ensure no leading or trailing whitespace on the remote_addr

Reviewed-By: Peter Rotich <peter@osticket.com>