Remove send bugtracker
As #8171 (closed) showed, this feature is not really used. I also checked the bug tracker database to see how much reports are sent via the client. It is very low.
Moreover, we the recent update of roundup, I'm not even sure that it still works because there are some new requirements: http://www.roundup-tracker.org/docs/xmlrpc.html#advanced-python-client-adding-anti-csrf-headers
With all of that, I think it is better to remove it and just leave a link like in sao.