Steps to reproduce:

1. Launch Hob
2. Select a machine (e.g. qemux86) and a base image (e.g. core-image-minimal)
3. Click 'edit image'
4. Select the 'All recipes' tab
5. Check any of the non-included recipes (e.g. alsa-tools)
6. Click the 'Cancel' button

Outcome: I am returned to the Image configuration screen, with 'Create your own image' selected as the base image.

Expected behaviour: the base image I selected as a starting point (e.g. core-image-minimal) should be selected as base image. When I select 'Cancel' I am asking for the image customisation process to be cancelled: any changes I've made to the base image should be ignored and I should go back to the state prior to selecting 'edit image'. The same behaviour should be applied if the process is cancelled in the Edit packages screen.