Volta brackets in scores?

[Mats Bengtsson]

When typesetting orchestral scores with repeats, you get
a volta bracket over each staff line. There used to be
a property noVoltaBraces to get rid of the undesired ones.
Now, I don't know how to get rid of them.

I thought for a moment that the solution was to move the 
Volta_engraver from StaffContext to ScoreContext, since
that would only give a volta bracket on top of each score
line. However, this is probably not the best solution, since
there could be lyrics or chord names or other strange things
above the top staff line, which should appear above the
volta bracket. 

Would it be possible to automatically connect the volta
brackets only to the top staff line? Waiting for that
ideal solution, we at least need something like the
old noVoltaBraces property, even though it's a bit clumsy.

   /Mats