Gitian update

This is an update for the gitian build files, and the makefiles for the mingw crosscompiled build of the client. 

It grouped together the removal of the OptionsModel::Upgrade() section into this pull request. This feature seems to be broken and has been removed from the bitcoin core code as well. It seems safe to remove this.

I also deleted a local file bitcoin_ca@valencia.ts.   The @ sign is conflicting with the gitian build system.