Fix for ImageMagick 404
Fix for ImageMagick 404

Looks like ImageMagick updated their patch level from `6.8.9-6` to
`6.8.9-10`, and also `6.9.0-5` to `6.9.0-9`

rmagick/rmagick,rmagick/rmagick,antonifs/rmagick,jonmartindell/rmagick,rmagick/rmagick,jonmartindell/rmagick,carsonreinke/rmagick,tvon/rmagick,antonifs/rmagick,jonmartindell/rmagick,tvon/rmagick,antonifs/rmagick,carsonreinke/rmagick,carsonreinke/rmagick,tvon/rmagick