Commented Unassigned: ImageMagick.MagickCorruptImageErrorException [1372]

This image seems to be valid in other apps but Magick (Q8-AnyCPU 7.0.0.0022) is puking on it with the following stack trace:

```
at ImageMagick.Wrapper.MagickImage.Read(Stream stream, MagickReadSettings readSettings)
at ImageMagick.MagickImage.Read(Stream stream, MagickReadSettings readSettings)
at ImageMagick.MagickImage.Read(Stream stream)

```

The message is "Invalid colormap index `' @ error/image.c/SyncImage/3563"

Comments: I have talked with the rest of the ImageMagick team and we decided to raise a warning instead of an error. The code now 'corrects' the invalid pixels and set them to the first color in the colormap. This will change in the next release of Magick.NET.