Make some tuples explicit to pass parsing in py3

examples/scratchnetuser.py

@@ -52,7 +52,7 @@ def scratchNetUser( cname='controller', cargs='ptcp:' ):
     info( '*** Starting controller and user datapath\n' )
     controller.cmd( cname + ' ' + cargs + '&' )
     switch.cmd( 'ifconfig lo 127.0.0.1' )
-    intfs = [ str( i ) for i in sintf1, sintf2 ]
+    intfs = str( sintf1 ), str( sintf2 )
     switch.cmd( 'ofdatapath -i ' + ','.join( intfs ) + ' ptcp: &' )
     switch.cmd( 'ofprotocol tcp:' + controller.IP() + ' tcp:localhost &' )