Enabling Pylint in RO and removing unused methods

Enabling pylint, removing some unused and erroneous methods,
updating required libraries.

Change-Id: I7ad823f83faa1fd9f055a92041cabc7a53f707ac
Signed-off-by: Gulsum Atici <gulsum.atici@canonical.com>
diff --git a/RO-plugin/osm_ro_plugin/openflow_conn.py b/RO-plugin/osm_ro_plugin/openflow_conn.py
index afc0b82..c41d7bc 100644
--- a/RO-plugin/osm_ro_plugin/openflow_conn.py
+++ b/RO-plugin/osm_ro_plugin/openflow_conn.py
@@ -286,9 +286,9 @@
         rules_to_delete = created_items.get("installed_rules_ids") or []
         new_installed_rules_ids = []
         error_list = []
+        step = "Checking ports and network type compatibility"
 
         try:
-            step = "Checking ports and network type compatibility"
             if ifaces_nb < 2:
                 pass
             elif net_type == "ELINE":