Clean up openstack network after failed instantiate

Signed-off-by: Jithin Jose <Jithin.Jose@riftio.com>
diff --git a/rwcal/plugins/vala/rwcal_openstack/rwcal_openstack.py b/rwcal/plugins/vala/rwcal_openstack/rwcal_openstack.py
index 68702bb..e06e311 100644
--- a/rwcal/plugins/vala/rwcal_openstack/rwcal_openstack.py
+++ b/rwcal/plugins/vala/rwcal_openstack/rwcal_openstack.py
@@ -904,8 +904,13 @@
             drv.neutron_subnet_create(**kwargs)
         except Exception as e:
             self.log.error("Encountered exceptions during network creation. Exception: %s", str(e))
-            raise
-
+            # This is to delete the network if neutron_subnet_create fails after creation of network
+            # Note:- Any subnet created will be implicitly deleted. 
+            try:
+                drv.neutron_network_delete(network_id)
+            except Exception as delete_exception:
+                self.log.debug("Exception while deleting the network after failure of neutron_subnet_create or make_subnet_args: %s", str(delete_exception))
+            raise e
         return network_id