Bug#1050548: meterbridge: ppm and vu meter backgrounds not redrawn properly

[Aaron Wyatt]

Doing a little more testing, replacing SDL_BlitSurface with SDL_FillRect 
fills the appropriate area defined by buf_rect with a solid colour and 
wipes out all traces of the previous needle. So I suspect this is really 
a bug with how the compatibility library is wrapping SDL_BlitSurface. 
Maybe this is better fixed in libsdl1.2debian? (Although this patch does 
act as a workaround in the meantime...)
Cheers,
Aaron