Avoid a SIGABRT in sun file handling This is a partial fix for malformed sun file
Bug: http://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=26857 Bug-debian: https://bugs.debian.org/832465 Origin: upstream, https://github.com/ImageMagick/ImageMagick/commit/6b4aff0f117b978502ee5bcd6e753c17aec5a961
