run: Fix running local repository images by name

Commit 79e6d55 ("run: Fix broken image detection logic") was overly
eager and broke Asias' workflow of running images from local repository
by name.

Fix it up.

Reported-by: Asias He <asias@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>