Remove storage_availability_zone from backend section

Change-Id: Ie2e3cbf0f866fcf57d6f0af61425c82bf8c75fb5
diff --git a/cinder/files/backend/_bdd.conf b/cinder/files/backend/_bdd.conf
index ae2b0a1..f2a07a3 100644
--- a/cinder/files/backend/_bdd.conf
+++ b/cinder/files/backend/_bdd.conf
@@ -2,6 +2,5 @@
 [{{ backend_name }}]
 available_devices = {% for device in backend.devices %}/dev/{{ device }}{% if not loop.last %},{% endif %}{% endfor %}
 enable_unsupported_driver = {{ backend.enabled }}
-storage_availability_zone = {{ grains.host }}
 volume_backend_name = {{ backend_name }}
 volume_driver = cinder.volume.drivers.block_device.BlockDeviceDriver