Talk up the 1.4 change to initialise volumes at  time

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)

this probably should have been in #9089
Let's simplify and clarify to: "As of v.1.4.0, container volumes are initialized during `docker create`. This allows you to, for example, run the following: