ImageBuf::write should be careful about the effect on ImageCache. (#1916)
ImageBuf::write should be careful about the effect on ImageCache. (#1916)

When we write an IB, it presumably changes the pixels, so we should
invalidate the file we're writing if it's in an ImageCache. Also, be
careful that were not writing an "in-place" file that hasn't been read
fully yet (because it's IC-backed).
lgritz/oiio,lgritz/oiio,OpenImageIO/oiio,OpenImageIO/oiio,lgritz/oiio,OpenImageIO/oiio,lgritz/oiio,OpenImageIO/oiio