We use glean in the gate tests to enable the network. Because we are
in a DHCP environment with the devstack environment, it's possible
that glean didn't start but we still manage to get an address anyway
via autoconfiguration. But the point of having glean is that in
clouds without DHCP things work too. This is most common with new
distributions, where glean matching may not have updated to configure
things fully.
We could replicate a non-DHCP environment, at some considerable
initial cost of figuring out how to setup devstack to do that and then
ongoing costs of having a fairly bespoke environment. A simpler path
is to just check the glean services and make sure they started
correctly.
Change-Id: Idb8d67cd2ba6e8c5d7157177e9cfd6be7b99cacd