With digests being added by default, all images have multiple references.
The check for whether force is required to remove the reference should use the new check for single reference which accounts for digest references.
This change restores pre-1.12 behavior and ensures images are not accidentally left dangling while a container is running.
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
Upstream-commit: 1f7a9b1ab3d261de5be7d490e7e4f978f317242f
Component: engine
ea3b59a83b