fix 1204: Changed the individual assignments for a chained assignment of the variables

Change-Id: I6d98ccd05b06f6d50596edea342a99546c737ced
Signed-off-by: fonsecaj <jpedrofonseca@av.it.pt>
diff --git a/osm_mon/collector/utils/openstack.py b/osm_mon/collector/utils/openstack.py
index 039ce61..b23bd24 100644
--- a/osm_mon/collector/utils/openstack.py
+++ b/osm_mon/collector/utils/openstack.py
@@ -31,10 +31,7 @@
     @staticmethod
     def get_session(creds: dict):
         verify_ssl = True
-        project_domain_id = None
-        user_domain_id = None
-        project_domain_name = None
-        user_domain_name = None
+        project_domain_id = project_domain_name = user_domain_id = user_domain_name = None
         if 'config' in creds:
             vim_config = creds['config']
             if 'insecure' in vim_config and vim_config['insecure']: