If convert is used with dcraw (instead of dcraw_emu), then dcraw
reports error:
1: No such file or directory
Convert doesn't use '$@' (-fbdd 1), so there is no reason to enforce
it here. postprocess.sh already detects dcraw
version (dcraw/dcraw_emu) and sets FBDD option. FBDD is supported only
by dcraw_emu.
Fixes: 8867b41a (Support graphicsmagick as alternative to imagemagick)