Fix new pylint errors

Fix the following new errors detected by pylint 3.2.0.
 - possibly-used-before-assignment

Change-Id: I06a5695e7e3ad3d645b81771cc1248046fdf8d68
(cherry picked from commit b0bfda27d0)

ovn_octavia_provider/driver.py

@@ -391,6 +391,7 @@ class OvnProviderDriver(driver_base.ProviderDriver):
         existing_members = pool.split(',') if pool else []
         members_to_delete = copy.copy(existing_members)
         pool_subnet_id = None
+        pool_subnet_cidr = None
         for member in members:
             # NOTE(froyo): in order to keep sync with Octavia DB, we raise
             # not supporting exceptions as soon as posible, considering the

ovn_octavia_provider/helper.py

@@ -638,6 +638,7 @@ class OvnProviderHelper():
            This function deals with updating the References of Logical Switch
            in LB and addition of LB to LS.
         """
+        ovn_ls = None
         commands = []
         if not network_id and not subnet_id:
             return commands
@@ -653,7 +654,6 @@ class OvnProviderHelper():
                 LOG.warning('Subnet %s not found while trying to '
                             'fetch its data.', subnet_id)
                 ls_name = None
-                ovn_ls = None
 
         if ls_name:
             try:
@@ -667,7 +667,6 @@ class OvnProviderHelper():
                                 'not found in OVN NBDB. Exiting.',
                                 {'ls': ls_name, 'lb': ovn_lb.name})
                     return commands
-                ovn_ls = None
 
         ls_refs = ovn_lb.external_ids.get(ovn_const.LB_EXT_IDS_LS_REFS_KEY)
         if ls_refs: