reader: don't set edit unit size when setting edit rate
reader: don't set edit unit size when setting edit rate

They aren't related and setting edit unit size at that point is not
neccessary.

stuarthicks/bmx,stuarthicks/bmx,kierank/bmxlib-bmx,kierank/bmxlib-bmx,stuarthicks/bmx,Limecraft/ebu-bmx,xunchangguo/BMX,xunchangguo/BMX,xunchangguo/BMX,Limecraft/ebu-bmx,Limecraft/ebu-bmx,kierank/bmxlib-bmx