Opportunisticly start mac rescan on rescan

While the network rescan might be too slow to hold up
general rescan, at least begin a rescan of switches
when a rescan is requested.

confluent_client/bin/nodediscover

@@ -289,6 +289,7 @@ def blocking_scan(session):
     list(session.update('/discovery/rescan', {'rescan': 'start'}))
     while(list(session.read('/discovery/rescan'))[0].get('scanning', False)):
         time.sleep(0.5)
+    list(session.update('/networking/macs/rescan', {'rescan': 'start'}))
 
 
 def main():
@@ -347,4 +348,4 @@ def main():
 
 
 if __name__ == '__main__':
-    main()
+    main()