oiiotool bug fix: bad argument parsing for --threads
oiiotool bug fix: bad argument parsing for --threads

lgritz/oiio,mcanthony/oiio,bdeluca/oiio,cwilling/oiio,OpenImageIO/oiio,scott-wilson/oiio,cwilling/oiio,lgritz/oiio,sambler/oiio,micler/oiio,OpenImageIO/oiio,lgritz/oiio,OpenImageIO/oiio,scott-wilson/oiio,micler/oiio,sambler/oiio,bdeluca/oiio,mcanthony/oiio,cwilling/oiio,scott-wilson/oiio,micler/oiio,cwilling/oiio,YangYangTL/oiio,bdeluca/oiio,scott-wilson/oiio,mcanthony/oiio,bdeluca/oiio,mcanthony/oiio,sambler/oiio,OpenImageIO/oiio,YangYangTL/oiio,lgritz/oiio,YangYangTL/oiio,micler/oiio,YangYangTL/oiio,sambler/oiio