When using a named volume without --volume-driver, the driver was
hardcoded to "local".
Even when the volume was already created by some other driver (and
visible in `docker volume ls`), the container would store in it's own
config that it was the `local` driver.
The external driver would work perfecly fine until the daemon is
restarted, at which point the `local` driver was assumed because that is
as it was set in the container config.
Set the bind driver to the driver returned by createVolume.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
