fixed formatting for quagga fast convergence merge

daemon/core/services/quagga.py

@@ -353,11 +353,15 @@ class Ospfv2(QuaggaService):
         if cls.rj45check(ifc):
             return cfg
         cfg += cls.ptpcheck(ifc)
-        return cfg + """\
+        return (
+            cfg
+            + """\
   ip ospf hello-interval 2
   ip ospf dead-interval 6
   ip ospf retransmit-interval 5
 """
+        )
+
 
 class Ospfv3(QuaggaService):
     """