Log Message:
Update ruby-RMagick package to 1.8.0.

Based on PR pkg/30171, I limit this pacakge available only for
ruby-1.8.X.  Though document says it works with Ruby 1.6.7 and
lator, it didn't build with ruby16-base pacakge.

Change Log.
	RMagick 1.8.0 - April 30, 2005
	o Added Image#shadow (ImageMagick 6.1.7)
	o Added Image::Info#undefine, #[], #[]=
	o Added sigmoidal_contrast_channel, sepiatone to Image class
	  (ImageMagick 6.2.1)
	o Added JPEG2000Compression constant (ImageMagick 6.2.2)
	o Incorporated RVG classes
	o Added RVG documentation, examples, updated installer
	o Tested with ImageMagick 6.2.2-0, latest GraphicsMagick 1.2