[INT] updating devstack install to use py3

- also fixing nova.conf post-config section

Issue-ID: INT-1419
Signed-off-by: stark, steven <steven.stark@att.com>
Change-Id: I9d4cfdf3d386a693e27c869a1326a80572a12323
diff --git a/deployment/aks/create_devstack.sh b/deployment/aks/create_devstack.sh
index fc136f0..63ce547 100755
--- a/deployment/aks/create_devstack.sh
+++ b/deployment/aks/create_devstack.sh
@@ -238,6 +238,7 @@
 package_upgrade: true
 packages:
   - resolvconf
+  - python3-dev
 users:
   - default
   - name: stack
@@ -292,7 +293,9 @@
       PUBLIC_BRIDGE=br-ex
       OVS_BRIDGE_MAPPINGS=public:br-ex
 
-      [[post-config|\$NOVA_CONF]]
+      USE_PYTHON3=True
+
+      [[post-config|/etc/nova/nova.conf]]
 
       [libvirt]
       cpu_mode = host-passthrough