virtex2 fix for bogus download error messages

The virtex2 FPGA download code watches for init going active during
a download of config data as an error condition. init also goes
active after a configuration is finished in concert with the done
signal. So far, the code does not check for done active until all
of the configuration data is sent. If configuration data has a few
extra pad bytes at the end, this would cause an error message even
though the download had suceeded.
NOTE: virtex2 slave serial and spartan2 versions may still have the
same problem.
Patch by Andrew Dyer, 12 Jan 2005