Destroy machines before destroying the model

Change-Id: If42c99ac9ec88a492d89a201f12a93872a476783
Signed-off-by: quilesj <e.nvi001.tid@telefonica.com>
diff --git a/n2vc/n2vc_juju_conn.py b/n2vc/n2vc_juju_conn.py
index cf865a8..00b1bc1 100644
--- a/n2vc/n2vc_juju_conn.py
+++ b/n2vc/n2vc_juju_conn.py
@@ -1240,6 +1240,15 @@
         model = await self._juju_get_model(model_name=model_name)
         uuid = model.info.uuid
 
+        # destroy machines
+        machines = await model.get_machines()
+        for machine_id in machines:
+            try:
+                await self._juju_destroy_machine(model_name=model_name, machine_id=machine_id)
+            except Exception as e:
+                # ignore exceptions destroying machine
+                pass
+
         await self._juju_disconnect_model(model_name=model_name)
         self.juju_models[model_name] = None
         self.juju_observers[model_name] = None