Divide OpenStack management access to admin and user

Divide OpenStack management access to admin and user

This patch adds OpenStack admin management access to the local "root"
user. Admin access is necessary to make changes to the default DevStack
configuration after its creation.

Package "python-openstackclient" is now installed globally (as root).
This is the reason why it requires additional flag
("--ignore-installed") for overriding packages already available on the
system - specifically PyYAML (3.11 available, 3.12 required).

Issue-ID: INT-1601
Change-Id: Ia5a1000f2f2066073c4e4a92fcb823eed17c36fd
Signed-off-by: Pawel Wieczorek <p.wieczorek2@samsung.com>