fixing controllers.py to use api

examples/controllers.py

@@ -15,8 +15,8 @@
 
 # Two local and one "external" controller (which is actually c0)
 # Ignore the warning message that the remote isn't (yet) running
-c0 = Controller( 'c0' )
-c1 = Controller( 'c1' )
+c0 = Controller( 'c0', port=6633 )
+c1 = Controller( 'c1', port=6634 )
 c2 = RemoteController( 'c2', ip='127.0.0.1' )
 
 cmap = { 's1': c0, 's2': c1, 's3': c2 }
@@ -28,7 +28,9 @@ def start( self, controllers ):
 
 topo = TreeTopo( depth=2, fanout=2 )
 net = Mininet( topo=topo, switch=MultiSwitch, build=False )
-net.controllers = [ c0, c1 ]
+for c in [ c0, c1 ]:
+	net.addController(c)
+
 net.build()
 net.start()
 CLI( net )