Fix AZ List Detail schema to allow hosts as None

List AZ with Details response can return host as None
for non available AZ from nova.

But response schema [1] always expect host as non-None
value which is not true for non available AZ on nova side.

Change-Id: I015ea26eb47ef179d55f3e452e871bfeec406365
Closes-Bug: #1662781
1 file changed