[vnet_route_check] Fix logic for getting VNET routes from ASIC DB (#1653)

Fixed issue when VNET route check detects some routes as missed they are really configured.
Signed-off-by: Volodymyr Samotiy <volodymyrs@nvidia.com>

Author: volodymyrsamotiy

scripts/vnet_route_check.py

@@ -266,9 +266,8 @@ def get_vnet_routes_from_asic_db():
         ip_addr = route_attrs[3]
 
         if vrf_oid in vnet_vrfs_oids:
+            vnet_name = vrf_oid_to_vnet_map[vrf_oid]
             if vrf_oid_to_vnet_map[vrf_oid] not in vnet_routes:
-                vnet_name = vrf_oid_to_vnet_map[vrf_oid]
-
                 vnet_routes[vnet_name] = {}
                 vnet_routes[vnet_name]['routes'] = []
                 vnet_routes[vnet_name]['vrf_oid'] = vrf_oid