clang warning fixes
clang warning fixes

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