This centralizes the lookup of devices so it is only done in one place.
This will be needed later when we change the locking for it.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Upstream-commit: e01b71cebeb96755641a18762dea5b843f107bee
Component: engine