Make 'prepare-docker' install proper docker-ce version

Docker-ce version should be aligned with Docker release
installed on target platform
(see build/creating_data/create-rhel-repo.sh)

This patch also optimizes package installation process
in Molecule tests.

Change-Id: I3f0cb7cd36a3f91027b2be43a925e54167d9c6d0
Issue-ID: OOM-1815
Signed-off-by: Bartek Grzybowski <b.grzybowski@partner.samsung.com>
5 files changed