Minor fix regarding "related" in WIM

Change-Id: I99c60a905009aa12513ab64dde5f64d164cca855
Signed-off-by: Anderson Bravalheri <a.bravalheri@bristol.ac.uk>
diff --git a/osm_ro/wim/engine.py b/osm_ro/wim/engine.py
index eecf10f..3fdd032 100644
--- a/osm_ro/wim/engine.py
+++ b/osm_ro/wim/engine.py
@@ -348,7 +348,7 @@
             'sce_net_id': sce_net_id,
             'wim_id': wim_id,
             'wim_account_id': account['uuid'],
-            related: related
+            'related': related
         }
 
     def derive_wan_links(self, wim_usage, networks, tenant=None):