Unhardcode AZ

Related-Prod: PRODX-3456

Change-Id: I219229c61dcc887e3cd59ffdc256cb29067a68f5
diff --git a/de/heat-templates/fragments/SrvInstancesBMCeph.yaml b/de/heat-templates/fragments/SrvInstancesBMCeph.yaml
index f3d4b7a..7c6a76d 100644
--- a/de/heat-templates/fragments/SrvInstancesBMCeph.yaml
+++ b/de/heat-templates/fragments/SrvInstancesBMCeph.yaml
@@ -73,6 +73,9 @@
   hardware_metadata:
     description: The content of lab metadata.
     type: string
+  availability_zone:
+    type: string
+    default: nova
 
 resources:
 
@@ -134,7 +137,7 @@
       image: { get_param: image }
       flavor: { get_param: flavor }
       key_name: { get_param: key_name }
-      availability_zone: nova
+      availability_zone: { get_param: availability_zone }
       networks:
         - network: { get_param: accessible_network }
         # NOTE(ohryhorov): connect to accessible network only as ironic doesn't