Preinstall yum-utils; move sudo check before install

Some cloud images don't have yum-utils installed, so the call to
yum-config-manager fails.  Pre-install it (I still think it's easier
than fiddling config files).

Also, these repo setup steps are using sudo, but the root/sudo checks
happen after this.  Move them up before we start trying to do
repo/package installs.

Change-Id: I875e1f0663c9badc00278b2cc1a3b04ca3dde9fc
Merge "Preinstall yum-utils; move sudo check before install"
Merge branch 'master' of github.com:openstack-dev/devstack