Blender Version
Date: 2018-11-29 15:57
Hash: 26d5a3625ed
Branch: blender 2.80 (Beta)

Short description of error
With mesh objects, in the contet menu, you can right click to set origin, but with a curve you need to go through the Object menu.
For consistency you should be able to right click on a spline and set the origin as well.