[docs] Update to use openstack CLI instead of glance(v1)
[docs] Update to use openstack CLI instead of glance(v1)

glance image-create --is-public option is v1 only. Current Image
Service API version is v2 and should be used.

This patch updates to use openstack CLI.

Related-Bug: #1527219

Change-Id: Ib846a37c90db59489724da7711a7c323d229ad76

NeCTAR-RC/murano,satish-avninetworks/murano,NeCTAR-RC/murano,DavidPurcell/murano_temp,olivierlemasle/murano,DavidPurcell/murano_temp,satish-avninetworks/murano,satish-avninetworks/murano,DavidPurcell/murano_temp,olivierlemasle/murano,olivierlemasle/murano,DavidPurcell/murano_temp,openstack/murano,NeCTAR-RC/murano,satish-avninetworks/murano,olivierlemasle/murano,NeCTAR-RC/murano,openstack/murano