Fix #8398 - volumes copying data unexpectedly

Prior to the volumes re-factor, data was not being copied on
volumes-from or host-mounted volumes.
After the re-factor, data was being copied for volumes-from.
This reverts this unintentional change in behavior.

Docker-DCO-1.1-Signed-off-by: Brian Goff <bgoff@cpuguy83-mbp.home> (github: cpuguy83)