Fix some options set by devstack
Fix some options set by devstack

* Use global var for Murano admin user
* Explicitely set keystone auth_url

Change-Id: Ib7b8f159bddc2260c2012a2c6ac3b2d8daa40fb7

DavidPurcell/murano_temp,ativelkov/murano-api,olivierlemasle/murano,telefonicaid/murano,chenyujie/hybrid-murano,openstack/murano,satish-avninetworks/murano,openstack/murano,olivierlemasle/murano,olivierlemasle/murano,sajuptpm/murano,DavidPurcell/murano_temp,sergmelikyan/murano,sajuptpm/murano,sergmelikyan/murano,DavidPurcell/murano_temp,NeCTAR-RC/murano,NeCTAR-RC/murano,satish-avninetworks/murano,chenyujie/hybrid-murano,satish-avninetworks/murano,olivierlemasle/murano,NeCTAR-RC/murano,telefonicaid/murano,DavidPurcell/murano_temp,ativelkov/murano-api,NeCTAR-RC/murano,satish-avninetworks/murano